Firstly thanks to all who replied, I only had one out of office is that a record?
The recuring theme throughout all the emails I received was to check that the Object Initiation Rules were set at the correct level. I had them set at Site level which should mean they are the master rules.
Another suggestion was to check my versioning scheme was matched to the 3.4 scheme. I checked that and it was OK.
Bryan and Rao suggested that it may be a bug with migrator M010. I am going to try another migration using F000 of the migrator and see if that works. I will post back with the results, hopefully next week.