yarntainer.com – Plaster identification and screw recommendation

Garmaine Staff asked 2 years ago

I need to fasten standard 15mm water pipes to a division wall in my house (built in UK in the 1970's). Some clips are already in place, but I need to add more (I am talking about clips like this: https://www.wolseley.co.uk/product/center-hinged-wrap-over-pipe-clip-15-mm/).

I am only familiar with brick, cement-plastered walls, so please bear with my newbieness:

What kind of wall and plastering do I have? See the pics of a hole in a wall on the same floor:

What kind of screws (material, size, shape, gauge) do you recommend?
Should I use plugs (anchors)? I unmounted one of the existing clips and the screw seems to have none.

Any further advice on what I should/shouldn't do, or anything else, is welcome.

Thanks!