Play in front propshaft

Right, I have just lifted jim by 3"( springs, shocks, front castor correction arms) but have not fitted front prop spacer.
I went out the other weekend and caused a bit damage, including ripping the clutch out! All damage sorted, new clutch fitted. But when I drive down the road at around 55mph I have a vibration, not horrendous but a vibration all the same, which seems to be slightly worse if I knock it out of gear and coast. I have been underneath (again!) and have noticed that there is slight play in the front propshaft in the spline area.
Now would this cause the vibration and have I caused the problem by not fitting a prop spacer, by fitting a spacer will this 'take up' the play.
Advice, comments or abuse all welcome!!

Mart

Ps have checked tyres,wheels and tyre pressures 21psi rear 17psi fronts, which is what Ihave always run.

Try it again with the front hubs unlocked, the front propshaft wont rotate then, and can't cause a problem, if the vibration has gone, mess with the front shaft, if not it could be an alignment problem with the engine/gearbox or transfer box, as you disturbed the mountings when you did the clutch.