Hi,
It sounds like you may not have a clutch problem. The gears can be shifted even if the clutch does not disengage. Can you get any gear to engage while rocking the bike back and forth? If you can get the bike in gear, you can immobilise the rear wheel and use the spanner to remove the clutch nut. This is a standard thread, counter clockwise to loosen.
If you cannot get any gear to engage, then you may have a problem with the shift mechanism.
Hope this helps.