Focus Timing belt change question

[Focustivct]

Going to be tackling the timing belt soon on an ‘05 Focus 1.6 Petrol. Sounds straightforward enough apart from undoing the crank pulley bolt to take the pulley off. I have read it requires the starter motor removing and the flywheel locking with the relevant tool. I’ll be using an impact wrench so is this strictly necessary? Can’t I just undo the bolt with the gun while the belts on without any sort of locking if I’m using the impact gun?

If I’ve got it right, time it up to TDC, fit the crank locking pin, whip the bolt and pulley off, bolt back in, make sure it’s still at TDC then fit the camshaft locking bar and do the usual?