I'm paying £1200 pa for above on a 2017 XFS diesel, current mileage 53,000 and I only now do about 3-4,000 mls a year, not sure whether or not to continue the guarantee,

(I paid £1500 to a main dealer last year to replace the timing belt, which they had to be done at 7 years) 

Hi Martin, welcome to the club. My XKR is 15 years old, 60,000 miles and still under the Jaguar manufacturers warranty. Only thing you know for certain is that a failure to renew at the annual subscription will guarantee a big bill, which in hindsight could just as easily have been covered by squirreling away the annual premium for the warranty package into a savings account.

N6 JMX