It would be as part of a AONE4, going Europe-USA-Asia-SWP-Europe, so not a problem for the 4 continent rule - it was mainly for the sectors - i'm trying to fit in as many sectors as possible, and as I can do MEL-LHR as a single sector on one flight number (BA18), this is better than using 2 sectors to do MEL-SIN-LHR on the same flight (despite dropping a whole 30 Tier points and only earning 330, instead of 2x180)
It's all currently a flight of fancy, but thanks for the help.