So he should call the RSPCA then... chsnging the locks leaving 4 cats trapped ought to cause the RSPCA to at least have a word with the landlord. He is already aware there are animals there before he changed the locks.
As for the OP having legal right to be there in the first place - he's been given permission by the occupier who has asked him to feed her pets...
The Landlord has no legal right to change the locks.
As for the OP having legal right to be there in the first place - he's been given permission by the occupier who has asked him to feed her pets...
The Landlord has no legal right to change the locks.