have you approached indespension themselves? if you're after a bunked trailer why not px it? They do a range called Big Dipper, which are bunked.
I'd be happy to do a deal with you myself, but as you're down that way why don't you have a chat with Tim and the guys at Tamar trailers? They sell Indy trailers and I'm sure they'd be up for doing a deal.
Tamar trailers: Tamar Towing Centre Plymouth