Option to delete unused VAT Code/Tax code configured by mistake.

We had a support call yesterday from a customer who had created a new VAT code and immediately realised they shouldn't have done so. They had already amended the description to "DO NOT USE" before calling us to see if we could delete the code. We didn't (though it looks like SYSTaxPeriodRateBalance and SYSTaxRate were the only tables that would need records deleting if we were to do it manually). Having a delete button (with suitable validation as to when it can be used) would allow users to correct their own mistakes.