The 4.4 and 4.8 cam sensor is quite well known as one of the weaknesses of that engine but to be realistic it does need to be in context?

I understood that it was a known fault but that this was mostly because those engines were actually pretty solid overall. Even more so when lightly stressed pulling an Aero at 1000kg's and not a loaded X5 and 2000kg's. It is not happening on a high percentage of them and when it occurs you just have a small repair issue not a total engine fail? Happy to be corrected?

If you want a shocker look for the Jag/Landy 2.0L IL4 wet cam belt issue or the same for the Peugeot (and a cast of ten others) 1.2L which is also a wet cam belt engine. If you don't keep a close eye on it and exactly the right oil/settings then expect to hear that lovely ping ping ping noise as the valves make jiggly with the pistons. Known for years and still in production. Ford ECOBoost 3cyl - same.