Bathroom lock - identifying which thumbturn I need

[ec5776]

I have a couple of bathroom doors with what looks like the same handle/locking system, only one of them is missing the spindle/thumbturn (I think those are the correct terms to describe it).

Here are two pictures I took, it's the bit circled in red that's missing - please see attached, as I can't work out how to display the pictures at a reasonable size inline within the forum post.

This is kinda tricky to explain in words but hopefully together with the picture someone will understand what type of mechanism this is. (I was trying to find a good diagram of it online but I didn't manage to find one, probably because I wasn't sure what it is called, and it doesn't seem to be the most common type nowadays; this fitting is probably 40 years old.)
I had a look inside the hold and it looks like as you pull down on the handle to retard the latch, the 'back' or 'rod' / 'tail' of the latch has a kind of two-pronged shape with a gap between them. I assume the idea is that you rotate the thumbturn one way, and the latch is able to slide past the spindle - this would be the unlocked state. Then when you rotate the thumbturn, it obstructs the back of the latch so that you can't press down on the handle - this would be locked.

Does this make any sense? My question is where can I get a suitable thumbturn, spindle and the fixing plates to complete the door which is missing those pieces, or whether those bits have specific names/types so that I can try to find them.

Thanks in advance for any clues you are able to provide.

[Someone-Else]

Would it not be easier and quicker to add a surface mount bolt to the door? Click me

[dewaltdisney]

These can be more trouble than they are worth. The idea is that you can use a screwdriver to open the door from the outside in emergencies. They are simple affairs with a serrated bolt that is pulled back and forth by the spindle. The problem you face is that buying a replacement in brass colour is hard these days as they are all chrome finish to match trends. The easiest approach is to start again and as SE suggests a new simple latch on the inside of the door and make good the door faces with a resin filler.

DWD

[Bob225]

What shape shaft does the thumb turn have ?

A google later

https://www.rocaindustry.com/product/th ... -320/#gref

[Bob225]

narrow oval

https://restorationsupplies.com/product ... bolt-locks

[ec5776]

Thanks. Yeah it would be easier to just put a simple bolt across the door, ultimately if all else fails that's what we'll have to do, but I wanted to explore the options to see if was possible to get a thumbturn with a spindle that would complete this locking mechanism.

I assume the thumbturn would have to have a shaft/spindle that has a rectangular cross section to fit through the gap in the prongs of the latch when the door is unlocked, but that is a guess. (If I look through the hole in the door when the handle is up/latch extended, it's a square shape; if you press the handle down to retract the latch, the top and bottom of the hole are obstructed by the 'pins'/'prongs' as they retract, leaving a rectangular shape between the two prongs).

In terms of getting one in brass, that is a second priority, as you can see from the pictures the one we have on the other door has been painted white anyway so it doesn't really matter what colour it was.

[Someone-Else]

Bolt it is then

[Bob225]

just an idea why not use a standard thumbturn they all come apart just use the bits you need (assuming the bar passes through the door) the escutcheons you have will clean up

https://www.wickes.co.uk/Wickes-Polishe ... m/p/253701

Replacement parts for the likes of the wickes part above

https://www.ebay.co.uk/itm/254618994454