You need to remove the tension from both timing chains by backing off the tensioners, which means removing the sump for the bottom, and removing the access cover to do the top, (I would do this with the engine pegged at the EP point), then prise out the ally bung in the front of the block in front of the oil pump, and there is a bolt that holds the intermediate chainwheel that needs to be removed. Then the oil pump shaft will be free to be pulled out through the chainwheel along with the pump.