There is a type of cable clamp/grommet which is in two parts, usually linked by a little plastic strap. You lay the cable in one half, then press the second part on top and squeeze them together, then the whole thing presses into a hole in a box.
I can't find any of these maybe because I don't know what they are called.
Can anybody help, please?

 

hi Albert.
These are split grommets.
https://uk.rs-online.com/web/p/cabl...s2GjWgPWpNqEC7W447RoCHj4QAvD_BwE&gclsrc=aw.ds

E

 

Yes, that's the things. Thank you.

 

If there is room, I always prefer these, easier to add/remove and easier on the cable itself:


Commonly referred to as "cable gland", and one size can do a range of cable sizes. (There are various size ranges)

 

I was looking for the other type because there isn't much room!

 

I can't find any of these maybe because I don't know what they are called.

I searched for "power cord grommet":

I hope those prices aren't for quantity 1.