The 50t outer ring on the wifes road triple has had it. Can I use one of these Stronglight rings as a replacement?

Depends, as long as the BCD matches then the worst that will happen is the ‘gates’ for shifting won’t be aligned and shifting suffers a bit. The only other thing is with some chainrings the ‘tabs’ are bigger/smaller than the ones on the originals so you have to file them down slightly to fit on the arms.

Cheers TINAS, that was pretty much my thinking so I’ll take a punt.

Also need to be careful if it’s a shimano chainset as the rings can be dished slightly on some models so if you replace (a single ring, ok if you do them all) with non shimano you can end up with the gap between rings being different and either issues with shifting or chains jamming in gap. More of an issue with the doubles but worth checking.