Forgot to mention: driving on British motorways is a pleasure! Especially in three-lane-motorways in Germany there are many drivers sleeping in the middle lane. For overtaking them you've to change to the "fast" lane. The UK drivers are much more disciplinated than the German ones. And rhey're using their indicators!
We love driving in the UK so much!
Are you sure you are in England:-?
This does not sound like any motorway I have driven on!
Regarding the drive shafts:-
They should push in firmly, and retaining ring should firmly locate the drive shaft, so it is not easy to pull out.
It might need a good "tap" with a large hammer and block of wood to locate the ring in the groove of the output shafts.
I would not want to drive unless they were firmly secured. Remember how tight they were to get out!
Peter