UK Car Repair: Jaguar MK2 hot starting, jaguar mk2, overflow tube

Question
I have a 1962 Jaguar 3.8 MK2 which is not used regularly, but when it is used starts from cold very well and runs well but when hot it will not start. The engine turns over fast but does not fire. If left to cool down for about 30 minutes it will start again no problem. I have had this problem for a long time and have done an electronic ignition conversion but that made no difference. I have also changed the coil ( not a new one though) and have also checked that there is a spark with one of those in line plug devices which you can see the spark through and it does seem OK. When removing the top of the float chamber (twin SU carbs)it has fuel to the correct level. I have also done a compression test on all 6 cylinders and they are all in the green area ( I did this when cold though). Could it be different when hot and is it safe to remove the plugs when hot? The starting carburettor seems to be working correctly and activates when cold for a couple of minutes.For interest it will push start easily when hot. Any ideas would be appreciated - I am at the limit of my knowledge and it is very inconvenient when at petrol stations etc. Thanks for any help
Graham

Answer
Yes you can remove the plugs when hot! But I am wondering why.  It can't be an oil drain as that is more noticeable on a cold engine, It can't be minimal valve clearances as the same thing would happen when the car was running and hot. It could be a fuel problem, how hot does it get? You can feel the float bowls to get an idea.  Are the breather washers fitted between the float bowl cover and the overflow tube? Some people use those "grosse Jet"  needle and seats -as opposed to the simple SU needle- and they have been known to cause such a problem. Now the fact that it push starts indicates an ignition problem, as the battery is not being used so full voltage is available to the coil and fuel pump! You could use a voltmeter to check the voltage at the different times! By the way does it have a ballast ignition system?