Yeah. Most of the time it's similar. A pg-13 corresponds to a 12 maybe 80% of the time, but the board decides each film case by case

A 15 in the UK unfortunately.

Sadly still a "15" in the UK, though it was rated "18" until reclassified in 2007.

It's not a question of whether there's anything bad in it but whether it meets the OP's criterion of being rated "12" or below by the British Board of Film Classification.

But Warm Bodies is indeed a 12, so great suggestion!

It's a 15 in the UK. Unfortunately, if this person's family are as strict about ratings as they say, they're not going to care that it's a pg-13 in the US, any more than a strict American parent will be assuaged by being told than an R-rated movie is a 12 in France, or whatever :)

Plague of the Zombies (1966) has good reviews (and is a 12), I haven't seen it myself though.

There are 147 missing episodes of the BBC TV show Doctor Who. The BBC didn't take care to preserve past episodes until the mid-1970s. I know that's TV. I think by then people were taking more care to preserve feature films. But it's still astounding to us today that they didn't look after episodes of one of their most popular dramas. The relevance of this, if it has any, is that it's therefore entirely credible to me that before 1930 or so, people weren't hanging on to films systematically as they would today.