VAT not charged on OLD customers after upgrade

[PudzPud]

Hi,
We installed the vat module around 18 months ago and its worked fine since however since upgrade to 1.3.8 existing european customers are not being charged vat however new ones are!

For example I am based in UK and get charged vat at checkout, all products i view on main website show price with and without vat. If I change my delivery address to spain, france etc it still calculates the correct vat. If a new customer creates an account the exact same happens for them with vat showing and calculated corrctly.

However, if an existing customer in europe (account created before the upgrade) places an order all products show the same price for incl and excl vat i.e. £1.00 excl vat / £1.00 incl vat and no vat is charged at checkout - even if a new european country address is added to the account no vat is charged.

The vat mod was a nightmare to install so removing and re-doing is really a last option for us as it may not fix the problem anyway but will create hours/days of work. Has anyone any ideas? We have too many european customers to try and locate them all the delete accounts so they are created as new ones and this has only started since the upgrade yesterday so must be connected to the problem but we have spent all morning trying to figure it out - as far as we can see all options in admin match the pre-upgrade options.

ADDED - just to clarify the vat module works fine and shows the vat correctly as it should, just not doing that with european customers who created their account before the upgrade - european accounts created after the upgrade are fine and uk works fine. With these old european accounts even adding a new address to them will not show up vat charges - its like the vat module does not even see them anymore.