Funnily enough, I had similar issues with the fast track at LHR T3. Fast track by virtue of status, however the scanners went red and denied me entry. I explained to the security guard manning the gate that I had access by status, they said they didn't really know what that is so just overrode the system and let me through.

It does sounds like you had a poor experience with CE, especially with the meal options and middle seat which to me is the main differentiator between CE and ET. It was very cheeky for your neighbour to use the middle seat, and I hope that they paid for the privilege of sitting at the 'pointy end'. Glad to see that there wasn't too much of a dent on your wallet, but sorry to read about your experience.

I would definitely take the opportunity to write a complaint, you may be able to recoup some of the avios lost from this.

Luckily I haven't encountered this but it's stories like this that really highlight how much a joke CE can be sometimes, especially if you have status in ET.