Did one a while back, a pain of a job.Dealers told me that there time allocated for the pump belt was in the region of around 3hrs. I can tell u now it took a lot longer.Its a very tight as your jammed between the engine and the bulkhead.

There is no way of actually seeing the belt properly ,so u better get a good mirror,a better torch and have the patience of a saint.To my recollection there are no timing marks as its only a high pressure pump.
One word of caution as i got caught out badly ,there is a very light belt guide tack welded to the pump pulley that came off after i did the belt and cut the new belt to shreads.Be very careful putting on the belt and take your time as I can tell u now u do not want to take off the pump pully.Good luck .