I wish I had a good recommendation for the contact. About a year ago, I had problems with one of my BBs and tried everything I could think of to contact them for a repair. But messages on their website, calls to the numbers listed on their site, and facebook messages were never answered. In this latest event, I noticed that they had a different number listed on their website. It was answered after 4 or 5 rings and a very nice woman told me how to get a repair. I realize you're in the UK so that's probably not going to work for you.
However, there doesn't seem to be a need for an approval, RMA, or anything of the like. She simply told me the address to send it to, and to make sure I included a note with the problem. my shipping address, and means of contacting me. It only took a couple of weeks for it to be repaired, and then they emailed a link to where I could pay on their website.
Not sure about the Royal Mail but the USPS has always been ultra reliable for me, and that's how it would be coming back to you. If you think that's what you want to do, the address she gave me was:
BBV
PO BOX 511
ATTN REPAIR
OGDEN, UT 84402-0511