I think this might cause problems because it sounds too much like a like-for-like change. People with may start with code like:
```
big_cube = iris.experimental.concatenate.concatenate([first_cube, second_cube])
```
... and change it to:
```
big_cube = iris.cube.CubeList.concatenate([first_cube, second_cube])
```
... only to be faced with the potentially confusing error:
```
TypeError: unbound method concatenate() must be called with CubeList instance as
first argument (got list instance instead)
```
Which might lead to them trying:
```
big_cube = iris.cube.CubeList.concatenate(iris.cube.CubeList([first_cube, second_cube]))
```
... and sticking with that because it does actually work. :scream:

So... how about, "Please use the `concatenate` method on a `iris.cube.CubeList` instead."? Does that help?