Surprised to see this....
One fact....
There is not Direct Heathrow Kathmandu flight.

So the route could be...... JFK ------>LHR ----->DOH -----> KTM, which is already in place.

KTM -----> LHR Direct, there used to be one from RNAC till 2001.... but u al know what happen after that !!!

I have heard that there is a new airlines starting to fly Amstradam (Netherlands) ----> KTM Direct , that may ease the pain !!