In the UK, 'chump steak' is probably more often used to describe lamb than beef. The equivalent part of a cow is more often referred to as rump steak:
http://www.allensofma...ages/alt/beef-alt.jpg
but Google shows a few references to 'beef chump steak'
Thanks everyone for such speedy answers. Looking at the site Nibbles suggested they are referred to as frying steaks. Think I might check it out with the butcher tomorrow.
A chump chop was, I think, cut fom the upper leg of lamb with a small round piece of bone in it. Could a chump steak be the same with the bone discarded.