An old box-spanner tommy bar and a piece of old heater hose. The length of the tommy bar isn't critical as long as the drill chuck is clear of the hole in the engine front cover. The hose is a snug fit over the end of the oil-pump drive shaft and prevents the tommy bar coming out of the drive slot.

End of the tommy-bar shaped with an angle-grinder to fit the slot in the oil-pump drive shaft.

Tommy-bar partially inserted in the hose.

Tommy-bar inserted the minimum depth. You can push it in further than this which puts more hose over the oil-pump drive shaft for greater security.