I may be wrong (usually more often then not) but the clutch separates the engine from the transmission. Operating the kick-start lever with the transmission in gear will result in the rear wheel turning regardless of the position of the clutch lever. You cannot manually start a Commando in gear with the kick-start lever regardless of the position of the clutch lever. Bump starting is another different issue.
If you want to know if the plates may be sticking then put the transmission in neutral pull in the clutch lever and operate the kick-start lever, The lever should operate smoothly with only a little resistance unless the plates are sticking and if so then the engine will try to turn over as the lever is pushed down.
After sitting for 6 or 7 years, yes it's probably stuck together. If it ever had some oil on the plates (dry clutch) the oil will have turned to goo, further cementing the friction and steel plates together.
You will need to make, borrow or buy a special tool to deal with the large cir-clip and clutch spring to remove and replace the clutch plates. If you get that far be very careful and remove and install all of the plates EXACTLY as you took them out. Do not shuffle them or flip them over, the cogs and teeth develop a wear pattern over time that match their position in the hub and basket.
It may help us help you if we know the year, make, and model of your Norton they are all the same but different.
Ride On
Dave