Removing Stromberg carb needles

[ratwing]

A friend's bought a Rover V8 trike with twin Strombergs and it doesn't run properly because not only has someone filed two huge great flats down each needle but they haven't even made the flats the same on each needle either so we're trying to get the needles out.
I don't know if this is relevent to the problem but the carbs have spring loaded poppet valves in the butterflies and a long white plastic bit on the carb body which I see is another emission reducing part.
We didn't think to take photos of the needles but they screw up and down in the needle mount/the threaded brass bit using a tool with a slot, not a hex key and are sprung loaded so if you pull them down they pop back up till the little 'circlip' thing (the black bit next to the grub screw slot) touches the bottom of the needle mount/the threaded brass bit. As best we can tell they'll look like this

We've removed the grub screws but the needles seem stuck in place - should they slide out or is force needed?