Bristan shower mixer - piece missing?

[StephenStephen]

Hi all,
I've a Bristan shower mixer which I want to reuse - it works fine, but I'm wondering if the slots - in the circle in the middle of the back - indicate that there's a piece missing to fix it into - a backplate? I can't see anything on the body where a grubscrew would go.
If so - any ideas on finding the right replacement piece?
Many thanks for your thoughts, Stephen

 

[oldbuffer]

It needs a backplate, which I think you'll be luck to get. There should be a grubscrew going through the back of the shower valve body at the back on the underside. Shower looks like Bristan KN2 SHXAR

 

[StephenStephen]

Yes - I'm a little confused that there's nowhere for a grubscrew on the body, and the flanges suggest some kind of 'twist to fit'

 

[Fred Blogs]

It's probably the plate that is fixed to the wall and then the shower unit is twisted to the plate to fix that to the wall. I would think it wouldn't be too hard to fabricate something to suit.