Is that flex you've wired it up with? LOL.

It will be fine - should be a smaller breaker for the sockets - 16A - but as the caravan site sockets will only ever be a maximum of 16A you will be fine.

Toolstation (I think) sell CTI stuff, but there are only 2 or 3 physical sizes, so some other makes will fit. It's the hole at the bottom that needs to be in the same place, but differs on some makes.