Hi,
Shropshires arne't that bad really, but Ryelands can be!
A professional shearer can shear most sheep without too much struggling, but if a sheep has been treated badly by a shearer before then they can be very bad.
Shearlings are good to shear as long as you know how and so are primitive breeds

.
If you are confident and relaxed about shearing then the sheep will know and should behave better.
I have had black eyes and bruises whilst I was learning but it all gets better after the first 1000

Thanks,
Philip