Nige,
I've had 2 Mk5's in the last 12 months, 1 with Interlagos, and one with Leather. It's so close, but given my colour scheme (Laser blue with dark grey and black trim and wheels) The dark grey leather pips it.
In other colours though, It may not be so close. The Interlagos is superb, and reminds me of my old Mk2 GTi 16V. Sorry, this probably doesn't help too much!