In reply to GraMc:
BD: will re-sling, for free - you just have to pay postage to the states, so it's actually good value. I found it very hard to get hold of them to book the service in the first place, but after that it went very smoothly.
DMM: will re-sling, and charge a sensible fee for doing so. Turnaround is obviously faster than BD!
Totem: will resling, cheaper than DMM, have to post to Spain.
WC: currently cannot re-sling. Last I heard they aimed to provide this service in the future but there's nothing concrete.