Hi all. I have been working out the magic number for the VAT increase on the 4th and have come up with 1.0212765. This is calculated by dividing the new rate by the current rate (i.e. 1.2/1.175)
If you run the following SQL all prices will go from 17.5% to 20%
UPDATE [DATABASENAME].[dbo].[tblKartrisVersions]
SET [V_Price] = (V_Price) * (1.0212765)
You will need to disable triggers in the backend first and also don't forget to change the tax rate in regional setup to 20%.
I am 99% sure this is correct so please check first and take a backup!
Hope this is of help for all of you running UK based stores.