has to be a DEEP socket (1/2inch drive normally do the job)
1/2 inch is normally a bit longer
1/2 inch is normally a bit longer
Can't remember using a deep socket for mine, has been a while though. it's the two right hand holes mate.
Aha! I spent 30 minutes going through old threads and they all said 10mm.. except one
So I tried the 13mm deep socket as suggested! and bob's your uncle it's A O K