Sun came out...
So popped out. ..and about 2 hours, mostly faffing about getting at it for what is a a 2min swap job.
So finally fitted the DMGRS 2-4 solenoid I bought 4 years ago .
But all in and the box is smooth again.
Took the end off the solenoid to find The problem..
Centre Should be connected to either or both the others
C