Item value charging twice when added to cart

I am using Zen Cart 1.3.8a with Database Patch Level: 1.3.8 and on certain items, mainly in 1 category when you add the item to the cart the cost is charged twice. Any ideas why this might happen. We installed a new shipping module recently but I have removed it and no difference. It may have been doing it for a while and I haven't noticed it??? The only other change it the web designers added another add to basket icon to the top of the item template, could this be adding the item twice, if so why doesn't it do it on all items? Help someone PLEASE this is driving me mad....

Is there one or two items in the shopping cart / order confirmation email?

DO you have a link to ur website?

If you take 1 item for £300 and add it to the cart, the cart says 1 item but value is £600???? Only happens on exhausts though!!!
web site is https://www.bikebits4you.com
Any help appreciated..

Strange. Even though I doubt if the template could cause this, I would try switching to the Classic template just to be sure. I would also try turning off your SEO URL add-on and see if that's it.

You are right. It is the template... Great. I paid for this custom template. I will have to go back to the designers I guess. I was hoping to sort this out myself. You are a star. Many thanks for your assistance