Thanks.

I'm still on the phone to the agent who's away to find his supervisor. He tried to point me to the terms and conditions where it says it's not allowed but could not find it.

The Chase 10% site says that the discount cannot be combined with any other offer. He's arguing that an Avios upgrade is 'another offer'. I'm disputing that and so he's away to find his supervisor.

I know I've done this before too.