I also agree they do like to steal a cassette we had it done on our caravan in storage some years ago..This is only a guess. Either a level sensor for the cludgie tank or possibly a reed switch from the caravan alarm to the compartment door in case some sad sort wants to steal the cassette. It does happen!
The bracket fits in a hole on the left of fuse as you look at the compartmentI have spent an age this morning on my knees trying to relocate this bit into its rightful position but in the end I had to give up because of knee ache!
Looks like a job for “Caravan Man”. 🕺
Thanks for your help ....🤗