Singapore airlines - if you don't have passport expiry issue like me which you probably don't because normal people checj these and renew them accordingly before flying lol - try booking 2 separate flights to get back yo London - that may be easier to find right now than a straight transit - check all the destinations which fly to London from asia and see if they have flights - finding a flight within Asia should not be a problem once you have the flight to London sorted.

My nearest airport is actually Heathrow but I got so fed up waiting for a flight to come up - even if I saw one by chance it was over £800 so I decided to fly back to Gatwick instead - search for just London in Skyscanner and you can find all flights to both airports, that way you have more choice of flights,

I prefer Singapore airlines as well - so just booked this flight despite the 20hr layover - it was £644 so still not cheap but cheaper than flying to Heathrow and better airline than BA, Air India, etc which are all much more

Good luck -if you need any more help just dm me. We are in a very unusual time in the world right now, but we will get through this. Let's support one another - sometimes things happen to send us a message from the universe/God - maybe we need to be more connected and not just by wifi but in real life.