I think the deposit is yours,
however he did act in good faith
and you are selling a crate - �450 for Gods sake
and return a very large part of the deposit.
I say this only because last week I agreed.....no I was charged a full day at a London hotel, because I vacated at 2pm and was told I should have cancelled at 6pm the previous day! When I left the room, it was not yet cleaned, and really �170 seems a hell of a lot for the use of a room for two hours.
Return most of the deposit - you will feel good about yourself and so will he.