Thanks very much for your reply.
I have tried deactivating all plugins and using the default theme, however this hasn’t worked.
I will speak to my hosting provider, however I suspect (as you mentioned) the issue is down to the sheer volume of product and the method of collecting the browser via Ajax.
I have used Gravity Forms for another online store,
however it becomes pretty tricky when wanting to update pricing, especially when there are so many variations to calculate a price.
This is why I have built variations as I can export and import a database of pricing.
Is there another way of managing this via a exportable database?
Has anyone else experienced this issue?