So I trimmed all the dead bits off last night as I didn't want to make it worse if it was a disease. Where the dry parts are there is no living tissue but on either side of the dryness there could be.
I think it had been in this pot a while before I purchased it, it wasn't root bound but the top layer was solid. I have repotted it and gave it a little water. Its probably the third or fourth time its been watered since probably may.
I've attached a photo of it repotted and the dry stems I cut off.