After 48 hours (that’s about 17 hours less than on the Wii U), my daughter and I have 100%ed it.
It was excellent. Certainly, it crashed quite a bit. And there were the usual bugs and things which meant getting stuck or having to redo levels, but it was a lot of fun, especially now it can be played with two players.
I did wonder if we’d come across the most frustrating of all bugs when we got to 99.9% complete and had nothing left to do. The stats show we had all the red bricks, gold bricks, characters, levels, and vehicles. Thankfully, I realised that helicopters (and the like) aren’t included as vehicles on the main list, and we’d collected but forgotten to buy one. Phew!