Installing a -US controller is not permitted in the EU:
The EU equipment approvals are based on the model number. The "Restricted Regulatory Domain - US" controller has a different model number than the "Unrestricted" hence we are not regulatory approved to deploy a US controller in the EU.
If you order a -US controller in the UK, the order is expected to be rejected.
Also, for the US both the APs and the Controllers must be deployed in the US by FCC rules.
I wished that I had better news for you, unfortunately, this is what it appears to be.