Hi
I came across a 10% discount code for the 6 day london pass , it may also work for the 3days
After selecting your pass, go to checkout,
at the very bottom of the page after Dining Guide there is "promo code click here ? line, so do that
a box will then appear ; the code is
10db
then click the apply code button,
scroll back to the top of the page, and your basket summary on the top right will display the discount.
regards
It's pretty much always 10% off and also generally a really bad deal (even at 10% off, which is how I bought it). See the thread: "Are there any coupon codes/ discounts for the London Visitor's Pass?"