The nearest one to me is Charnock Richard on the M6 in Lancashire. It’s one of the ‘services over the carriageway’ types with a KFC and Burger King upstairs on a bridge over the motorway and then Waitrose, Starbucks and Subway etc downstairs. Because it’s quite local to me I rarely stop there but I’d say it needs completely knocking down and rebuilding. It’s clean enough and the facilities are okay but the whole site is just knackered.
One of the problems with these types of services is that when the time comes for demolition, the motorway that runs underneath needs to be closed, probably putting off Welcome Break from doing this. I think if it were to be demolished, they‘d probably just remove the bridge section and not replace it, leaving two separate Northbound and Southbound services.
I think most of the ones with a restaurant bridge over the motorway should be given listed status! They are a reminder of a time when a motorway was an exciting new part of a holiday, rather than just a function. Someone told me that the fire brigade are not fond of having kitchens on the bridge section, so if it were rebuilt, you would probably be right.