This is pretty interesting, if I were at Morgan/Quaife (wherever the responsibility lies) I'd be getting in a tribology expert to come examine the box, preferably unopened with all components as they were at time of failure. I haven't read up about this issue much but is there possibly an aeration problem leading to insufficient oil film on the teeth?
I remember my tribology lecturer used to complain that by the time a company got in an expert, the failed machinery had been totally dismantled and in some cases the oil even thrown away before it could be analysed. Not sure about tribology experts in the UK, but Uni of Southampton might be a start.
For those who don't know, tribology is the study of contact surfaces in relative motion to one another and how to lubricate (e.g. here in the bevel box) or utilise the friction between these parts.
