Tacx Neo 2T - clunking, no freewheel and gears slipping

I have a Tacx Neo 2T, fresh out of the box. Have changed the freehub body to a campag for my cassette and bike set up. Have a 9speed cassette so used the spacer on the freehub body

Just done a first ride and a) it doesn't freewheel, b) it makes a clunking sound and c) the gears aren't changing particularly on the big rings. I'm not a bike expert - any advice? Have I set up incorrectly?