This may sound odd... However would it be easier or more sense to remove the engine to change clutch.
This way geometry won't get messed up and no need to struggle with box under the car.

 

If you have a crane then yes.
But can be done in situ.

Me I`d pull engine out, as I know how to do that lol.

 

if you have good access to a engine lift take out the engine mate.but i just norm take out the gear box.

 

Engine out it is.. Cheers guys..

 

+1 remove engine too

 

Another one here for engine removal. Gearbox out is tricky without a ramp.

 

+1 for engine route

Although my mate goes the gearbox way !

 

having tried both options its a +1 for engine removal from me , i dont have a ramp just the usual garage with clutter and a driveway , so far easier to borrow a hoist .
one thing i did find is the engine will come out without having to disconnect the air con system , which was nice , just , but it will with the condenser in place , just in case you didnt already know