Recoverable tax on Payables

Hi,

I need some help with getting a tax rate to calculate automatically when clicking the "Calculate Tax" button on Payables / Invoice Workbench.

I've setup the regime, tax, status, recovery, jurisdiction, rate and rules and then I can see this in Payables and select it manually - however, everytime I click the "Calculate Tax" button nothing happens. The expectation is to get a new line - a tax line - with an amount equivalent to the tax rate on a specific GL account that has been defined in the tax / tax rate.

I am at a lost as to why I can select it manually (there is only one option available under Tax Details so can't see why it cannot determine to use the only tax available)