Early in 1968, the US authorities changed the law on seats, in that from January 1969, all new cars had to have headrests incorporated in the seat. This left manufacturers with little time to re-engineer their seats, so Triumph literally welded on new tops to their current low back seats turning them into high back seats! These seat covers are in leather and are only available with plain flutes unlike its vinyl counterpart which is shown below. We would recommend you inspect your seat foams and straps as it is quite possible that they have disintegrated if original. We would also suggest you ask your professional trimmer to guide you through fitting these items.
Newton Commercial Part No - SC1539