Yanmar 2GM20F Replacement Ignition Key

[richelm]

Hi guys, my holiday home was recently burgled and the thieves took the house safe which, amongst other things, contained the keys for our boat.
The Yanmar C Panel is the small type fitted on early models (1988) that does not have the tachometer connected to a 2GM20F engine.
The key was a standard flat type but I haven't managed to source one locally (Yorkshire, UK) so was hoping one of you guys might know where I can get my hands on one. To my understanding Yanmar only supplied a couple of variants of these keys in this era but I could be mistaken. Thanks in advance.

[Sailmonkey]

I've used a flat screwdriver with great success is these key panels