Hi Nigel
Hope you have overcome your starting problem, but if you haven't, I had the same thing with my 1998 XJ8. After about two years of starting in neutral, I had a service and the mechanic found that the gear selector coupling was dry. Simply greasing the joint cured the problem completely. I believe the joint can be found close to the front end of the gear box. Good luck. best not to use WD40 it's not a good lubricant.