Whoops, my apologies.

https://www.bunnings.co.nz/irwin-speedbor-blue-groove-spade-bit-22mm-x-160mm_p0103012

Is this a reasonable "bit" to buy if I was to be drilling 22mm holes for the @blackjack17 recommended solution?

Also DIY dumb question, how do I line up where the magnet goes relative to the jamb magnet? 

Yep that would work.

Anything will do, you will only be using it a couple of times.  I would just go for the cheapest one available. In fact I would probably go for a set so that if I needed to drill a hole in the future I would have the tools.  Sets tend to be cheaper than individual ones.

Something like this

https://www.bunnings.co.nz/irwin-6-piece-universal-spade-bit-set-in-plastic-pouch_p0355931

networkn:

 

 

 

Also DIY dumb question, how do I line up where the magnet goes relative to the jamb magnet? 

 

It doesn't need to be perfect.  

You put one in and then make a mark with a thin pencil to line it up.

As above ^^

Speedbor are a relatively premium brand. Any kind of spade bit set will likely be fine for the few holes you will need to drill.

In terms of lining things up, I would close the door and make a (small, pencil) vertical mark across the door and the architrave. You can then transfer that vertical mark on to the horizontal faces on the top of the door and bottom of the door top frame using a square or ruler.

Close the door tight and mark where it stops on the top frame (along the face of the door). Half the distance between that mark and the door stops should be the mid point of the door. 

Measure along your first lines to halfway. On the door frame, add about 2mm towards the door stop. On the door, add about 2mm away from the door stop. This should give you about a 4mm offset between the door and frame - this is to help the magnets pull the door into the door stops.

In summary, as you look at the door with it opening towards you, the magnets should be in light left and right, but forwards and backwards the top magnet should be slightly further away from you than the door magnet.

Thanks for the advice. I went with the solution originally recommended by Blackjack17. It was an interesting time installing them, they are reasonably straightforward even for someone who should never, ever, ever DIY, like me :)

Time will tell if it's better, but the magnetic force isn't at all strong, even though I dropped one and it bounced, and I kid you not, jumped 2.6m (I measured it) to land squarely and loudly, on our washing machine.

It takes minimal effort to push the door open, but seems to be enough to keep it stable once there. We will see what it's like on a windy day. It's a much quieter solution on the whole, though it's noisy when it closes because it "bangs" against the bumper pretty much no matter how softly you close it. No soft close at all, which is a bit disappointing.

Now I just need to get my head around filling the holes left for the gear I removed. I've posted a photo in case anyone has any desire to make a couple of suggestions.

Not sure if anyone here knows, or can tell from the pictures. I know that our paint scheme is Resene Tea, Half Tea and I think Quarter Tea. I assume it's Quarter on the Ceiling, half on the walls, and Tea on the door areas perhaps?

networkn:

 

Thanks for the advice. I went with the solution originally recommended by Blackjack17. It was an interesting time installing them, they are reasonably straightforward even for someone who should never, ever, ever DIY, like me :)

 

Time will tell if it's better, but the magnetic force isn't at all strong, even though I dropped one and it bounced, and I kid you not, jumped 2.6m (I measured it) to land squarely and loudly, on our washing machine.

 

It takes minimal effort to push the door open, but seems to be enough to keep it stable once there. We will see what it's like on a windy day. It's a much quieter solution on the whole, though it's noisy when it closes because it "bangs" against the bumper pretty much no matter how softly you close it. No soft close at all, which is a bit disappointing.

 

Now I just need to get my head around filling the holes left for the gear I removed. I've posted a photo in case anyone has any desire to make a couple of suggestions.

 

 

 

 

Get some sticky backed foam and fit it at a suitable point for the door to close up against. That should reduce the noise.

You could have left the striker plates in place. They've always been there and wouldn't look out of place if they were left there.

Can you see the hole in the door under normal circumstances? If not, why bother filling it?

I still have the plates, I could reinstate them I guess, but I guess I'd like to "finish" the job :)

networkn:

 

I still have the plates, I could reinstate them I guess, but I guess I'd like to "finish" the job :)

 

 

 

Fair enough. Try something like this https://www.mitre10.co.nz/shop/selleys-permafilla-ready-mixed-filler-230g-white/p/129484 then sand and paint it.

P.S. I update my earlier post to add the idea about sticky backed foam. You may have missed that bit since you replied pretty quickly,

Technofreak:

 

networkn:

 

I still have the plates, I could reinstate them I guess, but I guess I'd like to "finish" the job :)

 

 

Fair enough. Try something like this https://www.mitre10.co.nz/shop/selleys-permafilla-ready-mixed-filler-230g-white/p/129484 then sand and paint it.

 

P.S. I update my earlier post to add the idea about sticky backed foam. You may have missed that bit since you replied pretty quickly,

 

I’m not sure Permafilla is really what you want for this filling job - it’s more of a surface filler and not best for filling holes of some volume. It will take a long time to dry in volume and will likely shrink and crack.

I’d suggest an epoxy filler like these:

https://www.mitre10.co.nz/shop/gorilla-builders-bog-500g-grey/p/370552

https://www.bunnings.co.nz/ados-250ml-builders-fill_p0272891

These cure by a chemical reaction and will not shrink like air drying fillers.

eracode:

 

I’m not sure Permafilla is really what you want for this filling job - it’s more of a surface filler and not best for filling holes of some volume. It will take a long time to dry in volume and will likely shrink and crack.

 

I’d suggest an epoxy filler like these:

 

https://www.mitre10.co.nz/shop/gorilla-builders-bog-500g-grey/p/370552

 

https://www.bunnings.co.nz/ados-250ml-builders-fill_p0272891

 

These cure by a chemical reaction and will not shrink like air drying fillers.

 

Agree, the gorilla product would be better. In my hurry to get the reply completed late last night the Permafilla was the first thing I could find.

Technofreak:

eracode:

I’m not sure Permafilla is really what you want for this filling job - it’s more of a surface filler and not best for filling holes of some volume. It will take a long time to dry in volume and will likely shrink and crack.

I’d suggest an epoxy filler like these:

https://www.mitre10.co.nz/shop/gorilla-builders-bog-500g-grey/p/370552

https://www.bunnings.co.nz/ados-250ml-builders-fill_p0272891

These cure by a chemical reaction and will not shrink like air drying fillers.

Agree, the gorilla product would be better. In my hurry to get the reply completed late last night the Permafilla was the first thing I could find.