P38 Diesel centralise oil pump on cranshaft

I have replaced the oil pump on my 1999 Range rover P38 2.5 diesel. However, before I proceed to tighten the 8 securing nuts I need to centralise the pump on the crankshaft. The manual says that I require tool LRT-12-116. Firstly, I can't locate anywhere that sells or hires out this item and secondly, I don't know if there are any workarounds using something else to do the job. (how accurate does it need to be?)

Any help would be much appreciated.