tmg513: I must say I agree with you and DaveW.
I'm not sure it is completely relevant, but one year ago I watched Wheeler Dealers when they changed chassis on a +4. They bought a lot of new pieces:
One main frame AND the 'frame front' (subframe), two leave springs for the rear axle, two complete uprights with king pins (adjustable camber), springs, callipers and disks. All of this £1600 (2012).
I'm not sure that WD pays any VAT or perhaps have a huge discount. Even if they don't/do I think there isn't any logical explanation for the discrepancy...
Interestingly DaveW told me that the Wheeler Dealer Morgan episode was voted by viewers as the second best episode and the very Morgan was brought over from Ireland for the Classic Car Show at the NEC last month which was hosted by the two presenters
I went but didn't know about its apparence until Dave told me when I was on the MMC stand