Got our pre-reg (Sept 2011), 16 miles on the clock 4Motion with a stack of extras (listing at nearly £52k) for a notch under £45k.
We paid cash though which may have made a wee difference. We were offered a pretty poor price for our p/x vehicle (LR Defender 110XS, late 2007) and managed to get £2k more down here selling non p/x to a dealer!!
I was initially a little unimpressed with the discounts being offered and felt the negotiations were very much one sided so we said we'd leave it (had placed a refundable deposit on it). This "stance" managed to knock more money off it and get about £300 more extras thrown in.
Play hardball, negotiate hard.
IMO Cali customers are very scarce. Can't be a huge number of camper van customers with £40-50k to spend that want a small van as opposed to a big mobile home? I may be wrong but while the Cali is absolutely in a class of it's own (small, fairly lightly specced compared to big mobile homes, but seriously high quality!) , that same characteristic reduces potential customers.