I dunno Alby.
The notification came through whilst I was logging Knocklofty ST41 so I thought who needs dinner?
Drove around here expecting the gate to be closed but it wasn't!
Located the required hole in the tank and logged on site. So here it is!
But wait! I quickly checked Surcom and found the actual trig is the grooved hole (next to my GPS and the 3rd hole for the tripod is being pointed to by the passing muggle (thanks - I think he thought I was totally nuts!)
So there you have it.