All sorted now, or almost.
Repair guy says rear of board fried, but is bridging what needs to be bridged.
Williamson Pumps had two of the old style boards left so I have had both, very helpful guys they were too.
One word of warning to anyone using Brodex. I have had this system over two years and it has been great. There was however a 40 amp inline fuse between the battery and the controller. There was a spare cable tied to the live cable. This should have been a 10 amp.
Worth double checking if you have the same.
Thanks to all for your helpful replies.