UK VAT - Tax tables

[Aldous Everard]

Is there any literature on, or can anyone help me set up tax tables.  I
have followed Vincent's tree when setting up my accounts heirarchy, and 
entered a transaction with VAT deducted.  However the VAT amount has
gone into the parent account (ie. VAT purchases) and I don't know how to
specify the Liabilities:VAT:I/P branch.

I am using Business | Vendors | New Bill to enter the bill amount.

Any help much appreciated

Aldous