thanks - i realised after posting that there ARE files in the EX800 folder( which i'm having trouble downloading, will try again in a bit).
video was very useful ! i have already managed to get the caps off, but it hadn't occurred to me that the switch itself disassembles. all makes sense now.
funny though that ranzee doesn't show us how to remove the black square cage supports :-)
i have a couple with a fairly weak click - not the ones i expected.
looks do-able, i'll see how i get on with it.
SECOND issue here, is that my buttons are pretty yellowed. wondering if the peroxide trick might bring them back - or do i even want to bother, if it could weaken the plastic... not sure if it's a permanent fix, either. can live with it, i s'pose. main thing is getting proper triggering back.