In reply to gear boy:
They fit if you remove the trig but do break quite easy (so far one, but Ron W has broken 3)
I have since removed the trig and packed the gap with washers and I'm hoping that will improve strength but I'm not 100% convinced.
The larger size grivel triggers fit and are effectively the same as the sliders (which aren't made anymore) once you saw off the metal trigger. Not heard of these breaking.