Weber carb and Costello Manifold?

[BJJohnstone]

Hi,

I am hoping somebody would be able to help me; In my grandfathers garage I have found a Weber carb (either 40/45 DCOE Weber??) attached to a cast aluminium costello manifold I think...
I was wondering if anyone could confirm this or add any detail as to what it is.

It's all in working order and good condition, anyone know what original parts like this are worth?

More pics available HERE.

Thanks
Bertie