BA Trident 2, complete with rear facing seats, INV-LHR in the summer of ‘79. Stayed one night in a B&B in Hounslow and the following evening flew to Malta on a BA Trident 3 for my first ever trip out of the UK. Two weeks later back to LHR on a BA Trident 3 (including a flight desk visit somewhere over the Alps) and then LHR-INV on a BA Viscount.
I remember the Trident 2 had the last 2 letters of the reg, FE, above the flight deck windows. This aircraft here I suspect:-
https://www.jetphotos.com/photo/5900283