Thanks all
Not sure how many there are out in the wild I know of 4 myself.
Each engine is marked with a number the highest number I have seen is 15 so far so there must be at least that many made , but how many survived I don’t know :p
Mine is mostly number 15 but with an engine from number 11 as the boiler was not in great condition. I sold the spare boiler as I don’t have the time to restore 2 of them 😄