It is an ENOTS double unit, on/off from inside the car and a pull reserve from the engine compartment, only fitted to oblong fuel tanks such as you have shown in your picture

Location: near junc 8, M25

thanks - does the main tap split/unwind from the 'base plinth'?
I dont want to force mine if it is one casting...havent seen another (not covered in paint) in the flesh to be able to check

that is SO useful. I understand their operation now too.
Mine is plugged with no 'arms' at all. (I hope both fully open!)

So what do people do with those tanks when that item is damaged, presuming those complex castings arent made any more?

Are there possibly any other fuel taps or connectors which can fit that double bolted tank exit hole?

They are very similar to motorcycle ones so may be interchangeable, although I have not tried it. Otherwise it would not be a difficult job for a machinist to turn them up for you.

Location: NZ

Mine was gobbed up with solder etc, initially I simply put a tap in the pipework beneath it, however it looked ****.

Eventually I made a brass flange, tapped female to suit a propriety fuel tap.

No reserve however.

a pic at the tail end of an engine transplant, I was contemplating the fuel pipe at the time

Have you tried to get a complete s/h one ?
Corks and a Viton O ring seals are available to repair them.

Thanks all. Ruairidh has also pointed out that if I've got a later engine with pump, its on/off function isn't technically required, and to leave well alone initially bearing in mind I'm on a 'get it safely on the road' agenda as a first push. [tax and insurance sorted last night - that should now be a spur to get the remaining bits of wiring fastened up]

If this car suits for longer term, then I can take off this 1930 tank (presently amidships) and put a later one under the rear.