My Estate used to go a bit left on a straight road then a few weeks ago I treated it to a set of Rainsport 5 tyres and afterwards it tended to pull right slightly instead. I swopped the front tyres over after 100 miles and bingo, it drives straight. No idea why but I’m not complaining!!

As has been said, get a computerised four wheel alignment done. This will give you a report on the entire front end geometry. If they've loosened the wishbone mountings that would put all the alignment out.