It would be interesting to know.
May be if there is no sign of too much play or other wear and tear one could say if it aint broken don't fix it.
Gavin, Trapeziums do not need services, only care.
However, if you feel there is some play or you want peace of mind, google Trapezium Developments in Roodepoort, they will be glad to assist in any way.
Click on the link below for their info.
Gavin you said it. Put ur mind at rest. Although good we should sometimes not worry about things that can go wrong until it happens. Earlier in the week I stumbled upon the thread on thrust bearings on the jacks. After I serviced my 4 jacks I asked myself if there is no damage to the threads then they should work effortless. I found I could turn all of them by merely having a long socket on the wurm head.
This means by modifying to add thrust bearing is perhaps something we do because we CAN and the effort would be less but not something worth the effort to change.
Please guys don't stone me it is just myself thinking a bit.
Glad you are sorted, at least, now you know from the manufacturer what is acceptable.