More Clutch Woes

I'm having a bit of an issue with getting the clutch working on my old 2000 M600 which has been sitting for quite a while.

The original slave cylinder was seized solid, so I bought a secondhand replacement complete with master, lever and pipe from a 620. Fitted it and then had a lot of issues trying to bleed it, but have managed to finally get that done. The lever is now nice and firm when operated.

However the clutch still doesn't work.

There are potentially two issues that might be causing the problem.

1) the "depth" of the slave cylinder seems to be about 2-3mm more than the length of the pushrod sticking out. I've read that there was a change in spec at some point and that a extension piece can be needed, but I think they are 10mm, which would be way too big.

2) The throw of the slave cylinder is around 1mm when the lever is pulled. Does this sound about right? It is very little movement.