A bit of give in tow bar.

I would check with the tow bar manufacturer what they say as this is something that needs their expert advice.

Yeah I will get the chap back round as he was a mobile fitter and  I still have his number .

Do you mean 'give in the tow ball' rather than tow bar? There should be absolutely no play in the tow bar which is tightly bolted to the car chassis. I did have a Discovery 4 with a detachable tow ball which had a slight amount of play. Landrover did a recall and measured the amount of play with a gauge. Mine was deemed borderline but I insisted I wanted it replaced as I was towing a heavy twin axle. They did so free of charge. From my experience talking with the engineer a small amount of play with a detachable tow ball was acceptable as it needs to be capable of inserting and removal. The important fact being that it cannot detach itself! I would recommend you get the engineer to check your tow hitch