Originally Posted by
OPebble
BA gate agents aren't normally empowered to do this; nor do they have the wherewithal - cash boxes; cc readers etc.

I think it is a good thing that these kind of paid for upgrades aren't common place, BA would no doubt see their revenues decline if people thought they could save cash this way!
As for "bing stuck" with what you paid for, you paid for WT+ and would expect no other, if you want to chance getting a very cheap upgrade then I think with BA you are setting yourself up for a fall in the first place. If you wnt to fly CW then you should pay for CW.