Call & Name
Hi John
Suggest you call them, speak to a supervisor and get his name. If still encountering a bad attitude after demonstrating your father qualifies, then let him know that you will not be letting it drop out of principle and expect to read his name in the Daily Mail.
Hopefully that would result in a attitude adjustment.
If they hide behind the cost of delivery; I'll happily receive at my UK address and get it to you.