Originally Posted by
SKRan
Since you mentioned BA5 I assume it’s Tokyo Narita (NRT)?
It's certainly not NAR (Puerto Nare, Colombia), as BA doesn't fly there.
On EF, LHR-NRT shows F being offered in both the current season and in NW 2019/20. So I don't know what the OP has been looking at, other than (at a guess) just looking for pricing and seeing nothing because the flights have no availability. Specific dates, if the OP's prepared to post them, would help with the answer.