RCD issue, or is it?

[the pict]

Changed a consumer unit everything fine all test came back hunky dory, but one RCD would not trip on the test button so swapped them around, same deal,I then got random trips from unassociated circuits IE kitchen ring plug in kettle and the opposite RCD would trip disconnect incoming earth RCD,s behave normally Ze .18 didn't clamp the earth to check any current flow did't think of it till on my way back, the only other thing I did after the tests was connect an outside light for the tenant to existing cable, so i am thinking a shared N any clues would be great
Dev

 

[polo1]

In the end it was a new LED hall light I put in before I took the old board out to give my self light to work as there was none there to begin with, I rigged it up from the henly blocks all kosher via a temp fcu,and it was the last thing into the board and this was causing the issue, as I said my plan was to remove the earths in turn till the tripping stopped and it was the culprit, what' the saying assume nothing suspect everything, well I assumed "cos its new it's ok" , all circuits test out great and as it is class 2 I disconnected the earth till scewjobs send a new one, cheers all for insisting I had a N..E fault
Pict