How to get rear wheel off on 307SW?

Hi
Noticed a flat with a puncture sitting on our drive. I managed to get
all 4 nuts out and put the guide nut in but when I pull the wheel just
won't come off. It is a rear wheel on a 307SW with alloys. I only have
the supplied jack so I don't want to pull too hard. I'm sure I have
followed the procedure in the user manual. Is there something else
holding the wheel on?. There is plenty of clearance so its not stuck on
the ground.
Thanks
Paul