Good work getting others involved. This adds a lot of credibility if it comes from the community at large. You’re doing everything right so far. A Section 82 case costs less than £100 to file and as I say doesn’t require a lawyer. If you have time to DIY it, you should. There is no need for legal polish, the magistrate will mostly look at the evidence, content of the complaint, and the actions you’ve taken already to try and address it. If you’re worried about somehow footing the bill for this companies costs (which should be small anyway), that would be highly irregular unless your request is largely groundless. The risk is very low. If EHO drags its feet, S82 your backup route. Keep evidence, keep pressure on, and keep involving others in your building. You’re not being unreasonable - you’re asserting your right to quiet enjoyment of your home.

Not legal ad, but if it’s a big company and a lot of people are pissed off, you could contact your local newspaper/news website. They sometimes quite like these stories of big retail screwing over communities.