Hi Ian
I think you have cracked it. The tie-rod ends do indeed have TRW stamped on them and now having checked yes they are M16x1.5mm. The supplied spares are all M14x1.5mm.
Thank you for shedding some light. I will remove the inner and outer ones on one side and go along to my local parts store and see what we can find in the catalogues.
Good news, she passed her annual MOT test today, they noted the play in the steering but said it was minimal and will certainly be fine for the time being.
best regards
Adam