Is it OK to leave a key with a neighbour to have some work done in the property?
No. We should be the only key holder. We cannot have the risk of strangers walking in whilst people who have paid money for a holiday are staying there, have personal items in the apartment, and may not be in the apartment at the time of the visit, etc, as it would not be acceptable, particularly if any of their personal items went missing because someone was in there whilst they were out. They would think that only we had spare keys so we could be blamed for anything. We would need to move any bookings until the work is complete. We may then require the the front door lock to be changed in case other copies of the keys are in circulation, perhaps because someone holding a key temporarily, particularly a workman, has had more copies made.