Just called BA bronze line to enquire about upgrading a current J holiday booking to First on the outbound. Availability was there but because of internal flight it can't be done online.

Telephone call answered within a couple of minutes and helpful agent was able to process the request no problem, disappeared for a few minutes to check the amount of Avios required (at my request) but came back with the answer apologising for the time taken but wanted to be sure as there were new changes implemented in the last 24 hours.

Booking already updated in manage my booking and seats allocated.

All in all a very satisfactory experience.

This will be our first First (LGW - UVF) and very much looking forward to the experience. Expectations are hopefully on set appropriately thanks to all the wonderful information provided here.