Thanks CWS. I finally got through today and got the UK BA Holidays Team. Was first told I couldn't use a GUF2 with an ex-DUB booking. Was put on hold and was then told it was possible. Then I was told I couldn't upgrade AA sectors, only BA sectors. I told the agent the GUF voucher terms had changed in May, was put on hold again and was told yes I could use on AA.
Then I was told no availability to upgrade on any flights (I had check Ireland POS on expertflyer, and double checked UK POS just to be sure). Agent said she was looking at reward availability. Asked her to check A class. Another hold and availability was found.
Agent did admit she hadn't handled a GUF2 voucher booking since pre-pandemic.
Finally got a quote, I asked to pay in pound sterling and was told ex-Ireland bookings will only price in Euros. Call was at 90 mins at this point and she said she would have to put me on hold to double check, so I just paid deposit in Euros.