I wonder if anyone here has used Coopers.  Or is it just a more expensive paint stripper than whats available at DIY shops 
The adverts look so promising.

https://coopersstripclub.com/

allio:

Looks like you will probably need to be sanding that down unfortunately.

I'm in the middle of a similar situation myself. I have no idea what's on my deck as it was applied by the previous owners. Pretty sure it's not oil based as it has come off a bit unevenly, but not in nearly such a flaky way as yours has. I've also recently replaced a bunch of boards so have some with no stain on them at all, so overall a bit of a challenge to get a uniform finish. I decided I needed to go for something heavily pigmented to stand a chance, so I've just applied one coat of this stuff in a fairly dark grey tint (Tiri). Didn't do any sanding beforehand as I can't be bothered to be quite honest. Fairly happy with the result as it's evened things up nicely but I'll definitely need a second coat for a properly uniform finish. Hoping it won't take a third...

Photo shows the old stain in the foreground, new Woodsman in the background, and unstained new boards on the steps.

Maybe the wood makes a difference to how the stain goes on (and comes off)? Mine is kwila, yours looks like pine?

Also I don't really understand what a "hybrid waterborne alkyd stain" is but it's definitely not just paint. It's translucent, dries with no brush strokes and has clearly soaked into the wood in a way that paint doesn't. Resene told me not to use the standard waterborne stain on a deck as it can't stand up to foot traffic but apparently this stuff can.

I recently completed full water blast for my deck (year old), followed by cleaning and Oil. 

I have used this product in Dark Oak. It was rated high on longevity on bunnings display. 

My Kwila deck was bought from bunnings (pre-oiled) and because it's only 1 year old it was not in a bad state before I started this work. 

It made a huge difference to the overall look though. Attached are images after 1 quote followed by completed 2nd coat. 

These two images are after the cleaning and drying before starting out the first coat on the corner. 

After fully doing the first quote - view from the top. 

The below two images are from the top after fully doing 2nd coat. (Wait 3 hours before 2nd coat). 

qwertee:

 

I wonder if anyone here has used Coopers.  Or is it just a more expensive paint stripper than whats available at DIY shops 
The adverts look so promising.

 

https://coopersstripclub.com/

 

I've unfortunately spent too much money on various chemical strippers - save your money and avoid them.

For a deck I would buy a cheap belt sander like this one. Get various grits and go for it. Stripping often needs sanding afterwards anyway don't use an orbital (slow), you could optionally hire a floor sander to get it done quickly especially if the deck is large.

maxeon:

 

I recently completed full water blast for my deck (year old), followed by cleaning and Oil. 

 

That looks so good. I think it's an easy choice to go with oil for a new deck. Even leaving it to silver naturally looks much better than the patchy tints you end up with with acrylic stain. Unfortunately when you've inherited one that someone else has had a go at, you don't really have that option unless you want to sand it into oblivion. And in my case there's a lot of visible tint slopped between the boards too so even a belt sander wouldn't be enough.