An Angel for May just showed up on Amazon Prime. I just saw it, and think of it as a YA (young adult) Outlander.
Significantly—or not—the Melvin Burgess novel on which the 2002 movie is based was published in 1992, or just a year after Diana Gabaldon published her first Outlander novel. I have no idea if Burgess read and was inspired by Outlander, but the two stories have a lot common. Time travel in An Angel for May happens when the hero, young Tom, walks through a broken stone facade of an old building. Both stories have a foot in the Second World War—the point of departure for Claire in Outlander, the terminus for Tom. Both are UK-based. And both are, in significant part, about the time traveler trying to change history.
But there are differences. A dog plays a role in An Angel for May, which is a lot less tempestuous than Outlander. There's a gentleness running through the story. Kids are the protagonists.
Time travel, in general, can try to reset history in two ways. The big way attempts something like killing Hitler or saving Socrates. The little ways are more personal, as in saving a particular person who never walked on the historical stage. Outlander has some of both. An Angel for May has just the latter.
Indeed, though Tom wants to save lives, what he's most focused on is improving the life of the girl he meets in the World War II past. What he's striving to do for May—who is a friend, not a girlfriend—is really a very little thing, with big consequences for her. It's refreshing and altogether excellent to encounter a time travel story on this scale, and I recommend it.