I've got the UK sales numbers somewhere I will try to locate them, but I have a feeling the 4200 & GS numbers are combined.
Parkers quote the following UK new prices:
> 2001-2006 4200: £56,695 - £67,950
> 2004-2007 GS: £66,735 - £69,130
So it would seem by 2006 there was only £1,200...