In EASA, land I'd argue that BA's safety reporting culture is second to none, and that comes from having a lot of dealings with various areas of BA on different safety matters. I used to work there and remember how strict they were that reports had to be made and followed up.
Certainly there are carriers in the UK and the rest of Europe who concern me, but BA have a very honest and open policy, its' the ones you don't hear about you should be most worried about. Aeroplanes and airlines are big, complex things, If nothing is going on safety report wise then either no-one is noticing, or they are deliberately not reporting.
SND