Reference Field on Quote and Invoice is not long enough

The reference field on the quote and invoice on Sage BCA is not long enough to give a decent description sometimes.

Also, when I prepare a quote, I usually put my customers' PO numbers in the reference box meaning the brief description I entered needs to be cut and pasted into the notes field.

What I would like to see is a separate 'Customer PO Number' field on the invoice which only carries over to the printed (PDF) invoice if an entry is made to the PO box (in the same way that the customer's VAT number carries over to the invoice only if the VAT number is entered on the Customer profile.

I'd like to be able to enter a decent size description, probably twice as long as is currently allowed.