Thanks to all for the comments. I think I’ll probably pay for the upgrade from CW to First.

However, what I can’t figure out is what effect this will have on my BA Miles balance. I currently have 34,000 miles and have a plain old Blue card.

According to my calculations I will fly roughly 24,000 miles on my RTW trip (LHR-SFO, LAX-SYD, SYD–MEL, MEL–NRT, NRT-LHR). I think I get some sort of multiplier for flying First (x2?).

I’m not sure if I will get a Silver card from doing this trip, but assuming I do, will I get the Silver card BA Miles multiplier (+25%?) for these flights or will they work on the basis that I have a Blue card when I start the trip so won’t get the extra miles?

Assuming I get both multipliers, I think I should end up with a total of 88,000 miles – does this sound right? Sadly it’s still not enough to get me a return CW trip to west coast USA…

Or have I got this completely wrong?