Mine lived it's life in leafy South London, hence no rust issues. I'd avoid anything Japanese which has lived by the coast in the UK 😉
There are good cars out there, just bide your time. I'd suggest not worrying about mileage and focusing on condition/history (such as the cambelt you mention). Mine had a few little repairs to the body in the past but living on the street in London does that to a car. I had the wheels refurbished and had the cambelt done (99k miles on the clock at the time). Now it's a great car and feels fine for another 100k, no clonks or rattles either, far better than the equivalent BMW/Audi/VW!