BKK-HEL-BER (Stop 1 in Berlin)
BER-LHR-ATH (Stop 2 in Athens)
ATH-CDG (Stop 3 in Paris)
CDG-LHR-SIN-SYD (Stop 4 in Sydney with a long transit back home)
And then resuming months later
SYD-SIN (Stop 5 in Singapore)
SIN-SYD (Return back home)
Would obviously find a positioning flight to BKK to start - but wasn’t sure if the SIN/SYD legs would work?
I just managed to secure a similar booking as detailed below. It was a nightmare trying to add the last two segments to an already ticketed itinerary. Was trying to add a trip to Asia, but proved too hard for the call Centre. So added a side trip into Auckland. Suggest do the booking up front, and not to add later, as it can get off rail, and you lose the already booked segment if Qantas does not re-ticket in time. Happened to me and took me 5 days to have the lost segments re instated, after going through some serious pains. Your Singapore stop should only be once. This is where I had the issue, when trying the Asia trip addition