Hi Steve,
I cant understand that to be honst and wonder if its some browser cache problem mate as its something that would undoubtably be very quickly reported and it never has been. Its far froma busy webshop but it does about 30 sales a day and nobody has ever mentioned such problems before.

I would suggest either deleting all cache, or probably easier, quickly install chrome or firefox and try it on there to confirm the issue?
Would love to hear the outcome mate, but worst case scenario we will honour the discount on the phone tomorrow if these problems are unresolved on your PC today.