There are demo yards renovation places that sell old window frames and doors, so imagine they would also sell knobs. But trademe is another option. YOu can also often buy new stuff that is almost identical to the old stuff, but may have more modern mechanics, but it can be very pricey.

In Wairau Park there is a furniture salvage yard - Timber Recyclers on Archers Road.

Places like early settler, sell repros,

http://www.earlysettler.co.nz/hardware/door-furniture

There was an awesome place in Christchurch before the earthquakes that sold that sort of stuff, I think it was called "Through the Keyhole". I don't know what happened to them after the quakes, I could never find them again.

jonb:

 

In Wairau Park there is a furniture salvage yard - Timber Recyclers on Archers Road.

 

Yes - thanks - this is the only place I was aware of and I phoned them earlier today to ask if they had stuff - they do and I'm going there tomorrow. Have bought there before - great place - love what they do with recycling native demo timber.

wellygary:

 

Places like early settler, sell repros,

 

http://www.earlysettler.co.nz/hardware/door-furniture

 

This is also an excellent idea - thanks. If I can't find genuine 'old', there looks like stuff here that will suit. Didn't know about this place.

Also try Junk and Disorderly in Northcote.  More of a traditional second hand shop but might have something.

kryptonjohn: How about these guys:
http://demolitiontraders.co.nz/recycled-goods/hardware/

Im nn ChCh, Musgroves has lots and lots of stuff. If you post pics or PM with pics I'm more than happy to have a look see. Its not far from me, and they have expanded big time. 

tdgeek:

 

Im nn ChCh, Musgroves has lots and lots of stuff. If you post pics or PM with pics I'm more than happy to have a look see. Its not far from me, and they have expanded big time. 

 

Many thanks @tdgeek - that's a very kind offer and much appreciated.

Back plate is 53 mm W x 165 mm H.

It doesn't need to be identical - roughly similar size and style would be great.

Cheers

Our local council operates a reuse shop.  I assume most council's do?  Another place to try.  I managed to find door handles that matched those doors in our old house at our local reuse shop. 

Also keep an eye out for renos in your area of houses the same age as yours and ask builders as often this stuff just goes in the skip.  I got a bunch of latch mechanisms when our next-door neighbours did a reno.

Often a local joiner 'back in the day' used a particular type of door furniture and you are likely to find it locally second hand.

No worries. This looks promising   http://www.thesalvagecompany.co.nz/windows-and-doors/

LOL, that place is not far from where I will be going Saturday morning, the old place we are selling, so Ill pop in there as well.

Try these guys...  but they are in the city.

http://www.bungalowandvilla.co.nz/