Thanks no6, so does this work then ams-lhr-sin-hkg-lax-ord-lhr-dxb-lhr-ams with stopovers in all places except last lhr when i'd connect direct from dxb to ams ? To get to the wedding i'd buy my own ord-lhr-ord and then re pick up my rtw later in the year.

I thought the "get back to origin " rule was changed (deleted) last year. You could do LHR-anywhere in UK-LHR anytime with 12 months of starting the ticket

Yes, that works just fine. Obviously you are only using 9 segments so could fly lots more, including 5 more sectors later in the US (e.g. ORD-SJU-LAX-SJO-LAX-ORD, or lots of other places in Mexico and the Caribbean if you fancy a winter vacation).

No - that would be 3 stopovers in the continent of origin (LHR, LHR, DXB) which is more than the 2 you are allowed.

(Deleted)

Quite right about the stopovers, I just assumed that AMS-LHR-SIN would be a transit (up to 24 hours) and not a stopover; the rules are desgined to discourage using the RTW fares for quick business trips.

well thanks for the info, never knew this would be quite so hard.
If I start from lhr, does this work or are you not allowed a trip on the end: lhr-sin-hkg-lax-ord-lhr-dxb-lhr (stopovers in all places)

It does not work: once you get back to the UK you are not allowed another international departure.

Still have not heard back from BA that my DONE3 is illegal, I called them this afternoon saying that I thought I needed to alter it, no one seemed to have a clue but told me its with a fares dept and will take a few days. Many thanks for all the insights.

Welcome to our world. ;)

If you originate in LHR, then you can do trips within the UK after you return but not LHR-DXB ... maybe LHR-MAN doesn't quite have the same appeal? You must originate in a different country in order to keep the Europe segments viable at the end of the trip.