Be fine at 30k just check the s/h and also what the next couple are, most people get rid before a big service.
See if it's had a steady 30k built up on it or if it's had nothing for three years then 25k in two years, you should be able to check from the s/h and the mots
I think 50k is the 100k for cars and 80k is pretty much dead, but I'm open for critisism