my other half has obtained a 10 year old car which was her moms, it has never been above 3000rpm, also covered about 20miles a month but had 15k on the clock after 10 years. The thing is a nail!! The car looks clean but the idle control valve had it, the engine didn't run smooth and in general it would stall when you stopped.
Spent lots of money on it to fix it, now I make sure it goes to its top rpm every so often.
On another note, JCW do need to be driven as designed, coking is not a problem through modern fuels, but settlement of particles will occur in the head if you do not open it up this can cause a coke effect though can be easily cleaned. Mine regularly goes up to 7200rpm and loves it. it always sounds nice and runs excellent. I do not race around but I use 3rd to do the motorway join in the morning and evening once warm 1-2-3 lane, good speed, used the high rpm then hit cruse and let it take me to work
happy days