That's a huge number of miles and quite unique for a car with a small engine. What kind of maintenance regime did you employ? Did you stick to the manufacturer's schedule or did you, say, change the oil more frequently? Just interested...the Up may be a good candidate for long term ownership similar to the Uno.
I did the maintenance on the car after the warranty period. I used duckhams oil which works but seemed to be able to encourage some good sludge in the cam box cover. I stuck to the manufacturer's recommended servicing which could have been 6,000 miles. I used a genuine oil filter.
The uno fire engine was/is a cracking unit. Large cam lobes sat on top of the buckets shims ad valves easy to change the cam belt. I can oly remember changing two or three valve shims in that time. I was always careful with warming the engine up before revving it.
Modern oils are much better so a good modern engine should last really well.
The Lupo GTi (not the standard Lupo), one of the best car I have owned by the way, was an all alloy body (except roof) - a little know fact. That and 125hp as standard made for a very exciting ride....and no rust problems.