I Googled “boxty recipe,” and the first ten hits all had buttermilk in them, except for one that asked for just plain milk. A few commented that they were a way of getting rid of leftover potatoes-- you had leftover boiled, mashed or baked potatoes, and you made a batter for pancakes the next morning, apparently, then if it needed a little more for the whole house, you could add some grated raw potato.
So, apparently, 2 things: milk is a key ingredient, which separates them from latkes right there, since a latke recipe would always be parve, since many people eat dairy on the first night of Chanukah, but meat the rest of the time, so you need a recipe that works with both. Then, the raw/cooked may be measured in a recipe from the internet, but there was no real standard in recipes of the past.
Not to mention, latkes were never a way of getting rid of leftovers. Since they were made for a holiday or festival, they would be made fresh. Unless it was during a famine, or some other really dire circumstance, you would never use leftovers for a celebration in Jewish tradition.
Nonetheless, they seem pretty similar. Not the same, but similar.
Although latkes are particularly well-known, it seems, outside of Judaism, probably because of their association with Chanukah, it seems to me that most traditions have some sort of potato pancake or dumpling. I’ve had them at Indian restaurants, Ethiopian restaurants, Greek restaurants (in actual Greece), I had them in Costa Rica, I understand there’s a Cajun version, and there are certainly versions in New England that are part of traditional cooking there. Every country in E. Europe seems to have one; they season them differently, and to different degrees, but they are essentially the same.