When my old house was reroofed, the scaffolding had to go over a neighbours flat roof. The scaffolder erected a fantastic bridge over it and it did not touch a single part of their property.
On another note, it seems as though planning is granted and work has started. Do you think that you stopping the scaffold down your side to brick up a couple of windows will stop the corporate machine? A bit like Swampy at a new road build? Will work stop and teams of builders down tools and sit there scratching their heads? I’d suggest big corporations have had dealings with stubborn neighbours before and have plenty of ideas, money and lawyers to throw at the issue. More than you.
Your main goal should be working with Co-op now. Not the builders, they just do as instructed. As said previously, if you stop all access, they’ll just block up windows from inside leaving a crap finish on your side. Easy. Who’s won then?
If you meet with a representative, you could relay some of your concerns - acces down your alley and I’m sure they’ll ensure it is maintained. The air con unit, by you being reasonable they are more likely to consider alternatives or explain the noise levels to reassure you. Sunday morning demolition, that’ll stop.
Fighting them now work has started is flogging a dead horse. On a plus note Co-op are doing boxes of Roses chocs for £2.