OK, so I took it all apart yesterday and cleaned it up, applied new grease and put it all back together.
Wasn't too sure if it all went back on the way it came off, for instance the actual cartrige bearing itself, does it have to go the one way or can it be turned upside down?
It all seemed to go well, even if at one point I was desperately trying to hold the bars, stem, bike and allen key at the same time without it all collapsing in a heap
Fitted it all back together eventually, bit of trial and error to get rid of the play before tightening up the stem bolts fully.
Couldn't get out to test it because of the Summer weather
but have just got back from a near 3 mile ride and it didn't fall apart so I am claiming success.
Oh, and the creak is gone