Sure it's not misfiring?
Misfiring can vary due to condensation, plug fouling, and for petrol
engines, bad HT leads, or a lead that has come loose from the plug
cap and is held in place by the rubber shroud.
Another possible cause of misfiring is restriction in the fuel supply,
which can be due to iceing in cold weather, blockage due to loose
particles in the fuel supply, water in the fuel, bad fuel hose in the
links between the fixed metal fuel piping and the engine, which
are there to prevent engine movement causing fatigue and fuel pipe
breakage. Fuel pumps can also fail and not deliver enough fuel for
the engines load, which would become evident on hills,

The clutch usually gives trouble moving off or changing gear.

The engine mounts are visible from underneath the car, they
support/attach the engine to the body. There is also an
upper engine mount to stop the engine rocking/moving
under torque, such as when accelerating.

Right, i should have explained, when i said its bad on hils, i meant
pulling away on them. Where excessive revs are needed to move the
vehicle.
I think it is a mount as the clutch is fine on hill starts(slow speeds)
and holding the clutch. It is fine on pulling away slowly, but if pulling
away at speed the car really shudders and vibrates.
I will check the mounting. Ive checked one, the one near the gear box, but
i couldnt see any others ;o(