There is no engraving on the bell, but there is on the 4th valve cover saying Boosey & Co and what as far as I can make out the number 515569. As Boosey merged with Hawkes in 1930, it must pre-date that.
If anyone can tell me any more about this tuba, I would be very interesting? Any pictures of Fletcher playing it?

I got it to a large extent because of its great rarity and province; and although am unlikely to use regularly, may well pull out for high register stuff (e.g. Bydlo) and it would be fun to play some British orchestral music on the type of tuba it was originally played. In fact I have Vaughan Williams London Symphony coming up in April. I have previously played on my Neptune, but might well try with the Boosey F this time!

Jonathan "who thinks better getting enjoyment from money in tubas rather than in the bank with the plummeting value of the British pound!"