Problems starting 411 on slight slope

[Martin9645]

Would any one have any ideas why my Bristol 411 has problems starting on my drive which has a slight slope so the car points upwards.
The ignition will click as if in gear (auto) but will not turn over.
At the moment I am putting this down to the gearbox oil running back (levels all good)
I may have to turn the key 20-30 times and then it will catch

Any ideas ??????