I have just converted rear hub to 10mm bolt through, but when I nip up the bolts the wheel doesn’t spin as good (as if the bolts are tightening the free hub) ?
Anyone else experienced this?

did you remember the freehub spacer ?

part 9 bottom pic iirc

I’am 95% sure it’s in but I will double check
Ps do you know if I can take our the bolts and use a 10mm q/r skewer?

Either a missing spacer, or the freehub seal isn’t seated correctly, presuming your bearings are all ok.

usually missing free hub washer they jump off and hide when you lease expect it, I think its a different axle if you want to use a 10mm skewer.

Ps do you know if I can take our the bolts and use a 10mm q/r skewer?

10mm bolt-up and 10mm bold-through(skewer) are different axles.

if the bearing isnt seated completly, it will also cause this.

If none of the spacer fiddling works, take a hammer to the bearing you took out to get the new axel in/out.

one hearty SMACK sorted mine.