7mm vs slightly broken 8mm HT leads

My 1992 1.6 currently has 8mm HT leads, but on one of them the plastic “handle” at the top of the spark-plug connector thing has broken apart - it doesn’t affect the lead itself as I can see that underneath disappearing down into the main part of the plug connector, just the rubbery plastic finger-grip covering has a large split in it.



How essential or not is the rubber cover to the operation of the leads?



I’ve got a spare set of new standard 7mm leads but if the 8mm ones are better and the damage is not affecting them is it worth sticjing with the larger leads?



Thanks

James

Try running your car engine in complete darkness to see if you have any arking across the leads, you might need to move the leads with a piece of wood to see if movement of the car starts them shorting out.