Hi all, curiosity got the better of me so after further testing I found the initial problem. The hydraulic lock out switch had developed a fault. When switched into the normal run position it was still locked out. But, if you applied just the tiniest bit of pressure to the switch (in the same direction) and held it that way it would switch out of lock-out mode. I must have pressed on the switch in this way when I was holding it to test it initially. Anyway, if anyone has similar symptoms it is a very easy check to do, just to rule it out Thanks.