Thanks jrudge. It is a Squadron 42. I will alter original post.You probably need to say what make and model of boat. My Fairline uses are plug sold in the USA as a trolling motor adapter. 3 pin twist in
Jrudge has linked to the sort of fitting you need. I doubt you'll find an off-the-shelf adaptor for this; you'll probably just need to buy the plug and cut the cigarette lighter plug off your inverter. If you're struggling to get one, give BCU a call and they'll sell you one as a Fairline accessory.
I have a marinco one on the boat. Ordered it off eBay from the Usa.
Also look in your Fairline blue document box as when new one would be great n that box.
It looks correct
How big is the inverter? I think these plugs are only rated at 16A, which is equivalent to about 200W output at 240V, and that's assuming 100% efficiency of the inverter.