Thanks for the very informative post as always - I'll give it a go tomorrow, worth a shot! Yes; these were all MilesAAver rewards.

FWIW; the initial mention was only to try and add context to why I was phoning to begin with rather than doing it online as a suggestion put forward on here. I wasn't aware of anything I said after that to provoke a negative tone aside from asking for a couple more date searches (which I think is reasonable if your first choice isn't available). Having worked in call centres for a couple of years in my youth I always try to be sympathetic and polite to agents. The second time was more to point out that I think there's a wider computer issue outside his control and that that I wouldn't waste any more of his time asking for more dates or routes (despite me needing to book some similar routings). I only went to "poke the bear" with the LHR > SLC idea after he made the comment about FT and his own knowledge about what was going on. But upon reflection yes; I could see how mention of how any source other than a BA employee or webpage could be "treading on toes" so to speak a bit and there were perhaps better ways to phrase it. The conversation here although long when typed was not everything in the call. For example after the first time he called me Bobby I did say "sorry but could you call me Rob please" (as I do have a pet hate against being called Bobby) and it's possible that also annoyed him and why he proceeded to use Bobby 3 more times during the call.

Thanks for all the extra information you posted as well - mostly all new information for myself and as I've only recently started travelling to the US a lot (and this will only increase) the info on AA/BA connections and redemptions is much appreciated.