Ok so I confirmed after a long drive that there was a very slight coolant leak (dabbed tissue turned red), got the torque wrench and set it to 20Nm and tried to turn it but there was very little room to move the handle, I managed to move it a bit but the amount of force felt disconcerting and the torque wrench wasn’t clicking, then because of the limited space I managed to accidentally pull on the connector with the socket and pulled it slightly to one side.
I didn’t try turning it anymore because it felt very tight and I was nervous about the torque wrench being off because 20Nm is it’s lowest setting. Drove to euro to get another sensor and checked it again and found that after the tightening it was no longer leaking. So my plan now is to get a second sensor and keep it around just in case but not change it now and go through all that hassle again, the connector moves slightly more than it should in one direction but it works perfectly and the connector is pretty snug, I don’t think there’s any chance of it breaking off.
Alls well that ends well I guess! Moral of this story is probably “if you’re going to wrench, buy decent tools”. I still don’t really know if my torque setting is over or under but next time it goes in for a service I’ll ask the garage to check it.