That sounds about spot on.
And that 52 in B52 could have come from 1952, always a giveaway...
Of course, in Kenya, where Burmans possibly don't grow on trees,
any functioning gearbox is a 'correct' gearbox ??
They don't look all that different, after all.
This is a view of a Yesterdays sale bike recently - any of it look familiar ?
https://www.yesterdays.nl/site/wp-content/uploads/2017/04/Mastchless-1953-G3L-2508-2.jpgAnd if you tell us that the local corner store has a stock of Burmans under the bench, I'll eat my words !
Especially if they are new, wrapped in greasepaper.