I have a view which already has SchemaBinding applied AND it has a UNIQUE CLUSTERED index.
Now, I'm trying to add a second index, which is a SPATIAL index ... and I get the following error message:-

And here's the a picture of the schema:

FFS - I found my answer.
Spatial Indexes cannot be specified on indexed views.
The error message is incorrect / misleading.
Cheers & Heads up to a previous SO question which is very similar.
Epic Fail again.

