If you already have had an account with them you may have some Scotweb points, and you cannot use both the xmts discount and cash in points at the same time. That might have been why your prices bumped back up at checkout.

I agree with sidnie that prices do not appear to have bumped recently. Actually, of all the UK sites I haunt Scotweb is the best on keeping up with changes in the GBP/US$ exchange rates as reflected in their prices. Many still try to price out items in US$ at a 2:1 exchange rate, which has not been accurate for several months now (more like 1.4:1).