1954 photo of modified 1935 3.5 Litre Lagonda owned by A.Imam of Bihar?
Wow! Youy know where to look!
That's exactly what it is, with one proviso not of your making - the builder claims that's the base car, but what 3.5-litre car were Lagonda making in 1935? Either it's a bored-out 3-litre or a dramatically sleeved 4.5 !
The owner/builder claims he won the 1954 Calcutta Grand Prix, a handicap event.
Very well solved indeed.