Thanks - will do. Now I just need to decide if it's worth an extra £25 to get my passport 1 week earlier in case of ESTA problems - this would potentially leave me just enough time time for a visa application if I still want to go ahead with the trip (though I might just decide to lose the cost of a cheap-ish flight and go elsewhere), but would make for an expensive passport

EDIT Actually - just realised I think it's too late for a visa if I don't get ESTA approval anyway. The earliest I could get a new passport is on Friday, and I'm flying out on August 22. If I'm refused ESTA approval, the London embassy has a 27 calendar day wait time for a visa meeting...plus 3-5 working days to prepare the visa...plus a day or two with the courier...which is just too a day or two too long. Let me know if I'm missing something, but if finding out about ESTA earlier won't make any difference I may as well just wait the extra time for the passport and cross my fingers...