Any idea what this is called so I can order some online?

The clip attaches to the feet/legs under the shower tray, and there’s a plastic surround which can then be fixed to the discs. There’s a two way adjustment which is quite neat (left / right and in out via the screw mechanism).

No idea but it will most likely be specific to the shower tray.

Good luck trying to order some online would have thought quite difficult to find.

Kitchens have similar fittings.

I would head to your nearest plumbing merchant, a proper trade one, and ask. Amazing what plumbers and the retailers know about which product / manufacterer it may be.

Plinth clip, adjustable ones don’t seem to be too common

Couldn’t find one the shape I needed but actually a length of dowel with a hole for a zip tie did the trick.

Thanks for the ID.

Can’t go wrong with some Heath Robinson