For the UK, there is a different policy to the US where if an exec room is not offered, then breakfast is the norm.

I've just checked into the Metropole in London and my Diamond reward was an "Upgrade" to a Deluxe plus room which as well as being miles from the entrance is "larger than a standard room". This allowed them to claim that they'd upgraded me and so met the terms of the weasel words in their offering.

It's also why I'm staying in a Marriott next week.

Upgrade to Executive Level or to the next best available room type (does not include suites, villas or specialty accommodations) subject to availability at the time of check-in. Only guests that receive an upgrade to the Executive Level will be given access to the Executive Lounge. At hotels that do not have upgraded types of accommodations or an upgrade is not available, Diamond VIPs will receive additional amenities and/or services, which vary by property.