Thanks to everybody for the advice - I tried cleaning the old keyboard as advised but to no avail (and I'm afraid I can't wait two weeks) so have managed to get hold of a refurbished keyboard.
Overnight delivery and the laptop is back on-line today!
Getting a keyboard for an five-year-old laptop wasn't as easy as it seemed - I wasn't too happy at trying the Ebay 'untested' offerings, but it was interesting that a couple of the companies I tried quoted £125 - £140 for the work, including parts, labour and VAT.
Now given that the part cost me £65 including shipping and VAT, and the fact it took approximately 5 minutes to remove the old keyboard and fit the new one - what kind of money must these people be making!!!???!?!
A sideline beckons methinks!
Cheers
SBG