Got the prop sorted fella, yesterday it decided to throw all its oil out in Wattisfield, bloomin oil pressure transducer came loose, so I tightened it and tore the threads out of the oil filter housing.
Anyhow, I have here a rangie sender/transducer like this one
http://www.autoelectricalspares.co.uk/lucas-sob302-drc2479-oil-pressure-sender--switch-1377-p.asp and I need to find an adaptor to make it fit the oil filter housing/adaptor.
I think the housing is m10 x 1 but I'm not sure. The sender seems to be 1/2" x 20 TPI UNF.