Got the starting problem fixed.
Had taken it to Nissan dealer and they diagnosed the reason it was slow to start was the fuel rail pressure relief valve and told me it could not be purchased on its own so I would have to replace the complete fuel rail at a cost with labour of $2600.
I had remembered reading a thread on here about a slow starting Patrol and re-read it and they had changed the valve on its own so then checked Patrolapart and they had the valve for sale so bought it from them for $300 and got my normal mechanic to replace it. (unfortunately my usual mechanic had not been able to diagnose the problem before)
Patrol starts normally now and with help from info on here I saved lots of money.![]()