Thanks for the replies guys.
Runs fine in smallest cog then when I shift it up its ok till the 8th gear then jams up. B screw adjustment just pulls the cage into the biggest rear cog if i try to give it any movement. Going to put a bit of extra chain in, see if that gives it a bit more room to manoeuvre. Not able to push it all way up with cable off, can’t see a DH stamp on it though :?