thanks for the welcomes folks
To cut a long story short - I sent a fairly angry and sarcastic mail to FGW▸ (First Great Western) yesterday evening, then forwarded it to Andrew Haines, and surprisingly received what I take to be a personal reply from Andrew Haines' BlackBerry (or whatever flavour of PDA he has) at about 11:30 last night. That was followed at 8:30 this morning by a 'stock' holding response from (presumably) his exec escalation team this morning saying that he would reply personally when he was able to.
He explained to me that he had been in the Nailsea, Yatton and Worle area last Friday meeting people and listening to their concerns, so it would appear that he at least is taking our concerns about the service seriously. I am a cynic generally, but I was pleasantly surprised by his response.