1936 engine troubles

[Irish Tom]

Hi Everyone,
I know I am only new to the Barn but I am asking advice again.

I took my 1936 out today, her 1st run in the last year. The car went about 4 miles and then started smoking out through the oil filler and though the small pipe coming off the inlet manifold.
The car is not knocking or does not sound wrong, it is running well apart from the smoke, plenty of power and no banging from the engine.

I hope its not something massive, I am near the end of a long 4 year restoration on this car.
Did anyone ever come across this before?

I am attaching a photo of the car as it is today, so close to resto being complete