Hide default VAT field so can edit control accounts, or make it so you cannot edit them.

Currently you can edit a control account and change e.g. the description. But you then cannot save the change because they correctly have None (input/output) VAT and this will not save.

Remove UI and backend Validation where the nominal is not a user defined nominal (i.e. control accounts only)

Also hide the fields Default VAT Input/Output and Unit Type from the form for control accounts and block changing the name of a bank account