Customer Groups not assigning correct tax class on frontend register
We have a clients who are beased in the UK, they need to only have EU customers with registered VAT umbers to be exempt from VAT.
We have set up Tax Classes and Customer groups that apply this correctly. When we manually add a customer to a customer group the correct tax appears.
However, when the customer signs up, personally, on the frontend, the system does not apply the correct tax rule, so when they should be exempt, they are charged VAT. If we view their account in the admin, then save, without changing a field, the correct tax settings apply.
We are really hoping someone can shed some light on this for us, could it be a caching issue, could it be we have missed something?
We've considered an extension to do this but we are unsure which will serve the funciton, so recommendation for extensions that can solve this are welcome.