Tricky, since BAH-DOH was scrapped. Flying out of London, your cheapest option tends to be a CE return from Gatwick. These tend to cost around £200, so £2.50 per point.

There are probably cheaper options if you can snag a cheap economy flight to the US for £300 and then spend £700 on American Airlines on what used to be YUP fares - tickets which automatically upgrade you to F. However, there are many on here who know a lot more about this than me .....

Intrigued as to why you don't want to move to Europe. The only reasons not to do it are

a) no Tesco miles (although you can put your vouchers in a drawer and convert them at a later date - they are valid for 2 years) and

b) no BA Amex (more of a snag, although if you can spend £10k in 6 months then you can move to Europe for 6 months and then move back and squeeze your spend into the rest of your card year)

And welcome to FT!