edit2: the whole unit, not just the DVD disc!
I'm not vouching for these guys - but just spotted the advert and figured it'd be worth sharing.... I've already ahd mine done: but paid 50% more for this from HazzyDayz... who I'm still recommending, given their friendly service, London location (and willingness to travel!).
Here's the new contenders:
Worth feeding back if people find there's dubious strings attached to the Prime Prestige "deal"...
edit1: glitch one: it's only Ł525 if you already have a double DIN setup (i.e. this is replacing a broken RNS-E or an old CD-based system).... it's Ł610 for the conversion... not AS good, but it still seems to be a pretty reasonable deal.
Feedback here if there's any other strings: extra charges for VAG-COM'ing it, updating software, proving the DVD disc, etc, etc.... the HAzzyDayz price was all-in.