I hate asking stupid questions but I have fitted new bearings. .I was careful that the bearings sat down on the step on the inside of the hub, but when I have tighten the shaft up the bearing is very stiff. To stiff to turn by hand but a spanner turns the hub faily easily. Should I strip it all down again???

Yes.
If it's that stiff without having had heat/distortion etc. it's not going to get any better.
Are you sure it's square in the housing?
Is it the correct size compared to the old one - even microns can affect smooth running?
Is the new bearing exactly the same configuration from to back as the old one etc. etc?
HTH.
Cheers, Pewe

What type of bearing is it?

Yeh I knew that really just thought I would check. Maybe a bit of grit underside. Oh well off it comes.