VAT journal in VAT module

Suggested

When I post my VAT journal in the vat module it has always been fine until last quarter where it has posted it with a T0 vat code and so has increased the vat liability in the next vat return.  The vat code set up in settings as the non-vatable code is T9, but it is posting it as T0.  I do not know how to edit this, as it will not let me edit the tax code in transactions, edit.  Any advice?