[NI_Volvo_Nut]

If you look at the crank pulley, you will see a block to one side of the recess where the main bolt goes through the centre, with this block at roughly the 8 o'clock position the mark on the flywheel won't be far away at that. you can flick the flywheel round using a flat head screwdriver of by raising one wheel off the ground (passenger side - support vehicle on axle stands) put the car in 5th gear and turn the engine over using the wheel.

OR

If you remove the pulley from the rear of the cam you will see a cut through the cam slightly off centre, with this lined up to the edge of the cylinder head the engine will be near TDC and the mark should be visible on the bellhousing.