Can anyone please advise the last stage of changing the timing /cam belt on a 1999 1300cc 323?

I have removed the pully belts, stripped the cam cover, removed the water pump and bottom pullys and released the tensioner.

The problem I have as i have never changed a belt on this car beofre is, do i have to undo the crank fitting to remove the belt or remove the sump? there is not enough room to pull the belt between the bottom crank fitting and the sump?

I am worried about trying to undo the crank fitting as I dont want the engine to go out of timing, I have marked it all with white paint so it can alwasy be realigned but when i put a breaker bar on the bottom bolt the engine is starting to turn even though i have it locked in first gear.

Any advice would be very welcome.

Cheers

TC