I find that a potty with a removable bowl is much easier than the cheap all in one potties. Just the shape of them seems they're not designed to tip into a toilet! Maybe it's just cause I'm American and we (as far as I knew, being the oldest of 7 children!) never had these "silly" all-in-one pots! It was always a potty chair with a bowl that slid in & out and usually had a pour spout which made it loads easier to pour, IMHO. I found a Safety 1st potty which has a bowl that slides out, though it's rather a huge bulky object, but lots better than the others, I think!
Tho maybe no one else has problems with potties! lol