I've PM'd Keith, but just in case there are any other raving DIYers out there, the code for the U channel is IRS1168N, and last October, 3 metres cost £4.23 including P&P and VAT. The catalogue (on-line or paper) has loads of channels/extrusions.
DaveW '05 Red Roadster S1 '16 Yellow (Not the only) Narrow AR GDI Plus 4
