David,
I have had a chat to the people that help us out here with our site mate and I have copied there reply
below for you.
Hope it helps you out a bit more if you are still having problems.
Regards tim
Greg Lawrie here - I provide technical support to Ultimate Reptiles.
I have had a look and there is not really anything from the server end that can cause the problem you are seeing. The Grunt Payment Gateway is the transactiion processing system that the Ultimate Reptiles website uses for its online shop. However, it is on another server, and in fact hosted by another ISP, to that which hosts the Ultimate Reptiles website.
I am pretty sure that the only way you could be seeing this effect is if your system (or ISP) has cached the payment page at some point in time while you were making a payment for an order. The way to try resolving this (assuming you are using Internet Explorer) is firstly to click on Tools, select Internet Options and then click on Delete Files button on the page you are looking at. Click on OK and let it go. Once it has completed you should be able to click on OK once or twice to exit from the options.
Try that out and see whether it makes any difference.