Identifying a classic bike

[montymoo]

Mainly out of curiosity, but is anyone able to identify my grandfathers old motorbike.
My dad sent me this old photo but I’ve no idea.



He did send over some other photos but like a pillock I’ve managed to misplace them.

Cheers for any help

[NITO]

Great pic,

I'm going to go with something like a Matchless Sunbeam, it has a pushrod engine, looks circa 1930's ish.

[srob]

I think it might be something like an OK Supreme. As mentioned above, it’s a 1930s bike.

Will have a proper look a bit later

[littleredrooster]

Could possibly be a JAP engine, so something from any number of small manufacturers who used that power plant.