John Lewis - £10 off

Got a letter from John Lewis saying they now accept AMEX -
Old news, I know,
but it also says you'll receive £10 off first purchase of £100 or more on-line using your Virgin Atlantic American Express Card.

Tried it, but website says I've already used it..
Anybody had any luck with this?

http//www.johnlewis.com/amex

Had a look and one of the points in the Terms and Conditions is:

This offer is available to first-time customers only

Not too sure but may mean the offer is only valid to those purchasing through the website for the first time?

Jonathan