So this is what arrived today:

https://www.amazon.co.uk/dp/B071DXGG..._TE_item_image

Must say I'm quite impressed. A sintered filter and a one way valve on the fluid line. Two needle valves and a 5/16" air line push fit. Rigged it up to a small air brush compressor and it works a treat. Obviously I need a bigger compressor to get max air flow but the venturi works even at air brush outputs.