Generally in the UK I’ve learned that what we consider ‘high’ mileage is actually more like average or moderate mileage. This means there’s a sweet spot for cars with around 60-70k miles that are way more affordable than they’d otherwise be, and are usually just as reliable as everything else so long as they’ve been maintained. Like the other guy has said you’ll still pay out for maintenance, but this tends to be cheaper than PCP, lease, or other finance products.

Ex-fleet cars are good for this as they tend to be mostly motorway miles and have been maintained as per contract requirements, so offer a better-than-good chance of being a hidden gem.

The Jags you’ve been looking at are examples of this as a lot tend to be company cars.

From discussion about this with friends, it is felt that exceptions to this rule are things like pickups, vans and other commercial vehicles.

Obviously the usual disclaimers apply - always inspect, look up history, check the service logs and drive a vehicle before purchase. Also, with any second hand purchase there is an element of risk, but lots of dealers offer warranties to protect against the dreaded lemons.