You had a contract with the original owner that a dog would be permitted to stay, this was a condition of the contract though this may be difficult to prove in the absence of a written contract unless you booked by post and received written confirmation. I can however think of no one who would travel the distance you did on the pretence of a correct booking.
Write to the new owner making the point you had a contract and they did not exclude consequential losses therefore you require the return of your deposit together with the cost of making alternative arrangements which they (the new owners) could foresee. Do not be to greedy with the cost of alternative arrangements, set a time limit of 14 days for repayment, and if that is ignored send a further letter headed “ Letter before court action” and state that if repayment is not received within 14 days you will take action in the court to recover the amount. If this is again ignored start action in your local county court, not any other county court.