A look for hose fittings to fit the listeroid engine revealed two things.....
1) They are expensive here in North America ($30 each typical)
2) There is TWO type of BSP
BSBT (British Standard Pipe Tapered) similar to our NPT (National Pipe Tapered Threads)
BSBP (British Standard Pipe Parallel) similar to our NPS (National Pipe Straight Threads)
Of course the engine plug does not say which one...............
I will assume TAPERED threads because that is more common in piping systems.
I found these at "The Hoseshop" in England. Relatively inexpensive.
I have contacted them and they are determining shipping costs by Postal Service
rather than courier (expensive + brokerage fees)
)
Best regards !!!
Bill