I have created new main account categories to link to our main accounts that relate to the P&L.

I have linked the account categories accordingly, and can see the link in the relevant field on the main account.

When I try and build a P&L in Financial Reporter using the category instead of a range of main account numbers, nothing appears in the actual report when generated.
I can only think there is some further set up for this to integrate, but I'm going round in circles looking for it. As I understand it, the main account category is not a dimension.
I'm using a test system into which we have copied the Production environment. I read something about refreshing the datamart if a copy of the database was being used.
Please can anyone advise?