Call them, talk to them, they are lovely the times I've spoken to them. I had a RD missing half her tail, after explaining why I couldn't go back to the store I got her they sent me a replacement in the post. They did say they couldn't guarantee a RD but I was lucky I got her and two other extra ponies. I also recently called them again about SA & PC in the castle wedding set, SA's tail was not good at all. Again, lovely and sent me out replacements for the ponies for me.
I've used the number a couple of times for product information. If they don't know they'll tell you but seem happy to find the information out if they can.
I don't know if I can put the phone number directly on here but it can be found under their website, it's the 00800 number on there saying consumer affairs.
http://www.hasbro.com/en_GB/customer-service/Edit: Ahh Hathorcat, you replied while I was typing this up