You can change the currency using the function at upper right of page (next to shopping basket icon).

I don't see the mark-up issue you mention. I looked at 5-yarders with XMarks discount, and saw the bespoke offered at $300 marked down to $265 and change.

Then I cleared the XMarks discount (see "clear/view all offers" link at the right end of green bar) and price went back up to $300.

Perhaps you had cleared cookies at some point and lost the discount? Try clicking through again from the banner ad and see what happens. . .

Good luck!