How do I bathroom / kitchen / extension? etc.

Do Hafele not make one? Otherwise I'd try Daro, but they may just stock Wesco ones.

What's the issue out of curiosity?

Last week we were staying a a mates who had a bin the same design as that and it seemed great. It's a Howdens kitchen. I'll see if they know what it is.

Vauth-Sagel are good.

I have the Howdens 400mm pull out. Same principle as yours but from the picture I'd say it's a bit more sturdy, if that's what you're looking for?
The shelf above is annoying to get anything out of though.