I presume TWOV means travel without visa? Sometimes there's too many acronyms.
Anyway I've done that exact route several times (to Delhi on BA and then KAthmandu on Jet Airways or Air India), never been any problems.

A word of warning, though: Be prepared for a long wait in Delhi while the staff sort out your onward boarding pass. Shortest time it's taken was 1 hour, longest was 6 hours (which was KTM-DEL-LHR in F) Last time I did the route I was told that the staff member they needed from BA was "at home and not willing to come in". Explains why it was the last time, now I fly on Qatar.