Just to update that the new gearbox that was fitted has the longer 5th and 6th ratios! I didn't realise until I'd spent some time on the motorway and it seemed a little less buzzy - a glance at the revometer at 70mph shows 3,300 rpm instead of 3,600 rpm!
Trile: the symptom for me was a nasty gear crunching noise when engaging 3rd.
Trile: the symptom for me was a nasty gear crunching noise when engaging 3rd.