Unacceptable senior management - Here's my experience. - Server/Bartender Tasty Employee Review

I worked at Dim T Charlotte Street for 5 months in 2017. During this time over half the staff quit, including managers and supervisors, all of whom I considered good people to work for. A new member of management was hired who was clearly unsuitable for the job; two people quit within his first week. I filed a written grievance complaint against him, after which I met with someone in Head Operations. They spent this time complimenting me on the way I wrote the letter, my intelligence, and educational background, as if these things were relevant, and assured me there would be two follow-ups: the written minutes for me to approve and have a record of, and a follow-up soon afterwards. There were no follow-ups. Both of them pretended like none of it happened. Aside from the disregard of a formal procedure, two people in managerial positions could not face up to a minor conflict in the workplace. From a North American's point of view, this was absurd--borderline funny. Except it isn't funny, for this is how minimum wage workers in the UK get treated every day, under the mismanagement of irresponsible people (I know for a fact other staff's complaints were not taken seriously because of their socio-economic background) - where is their pride in doing genuinely good work? I was leaving the UK and didn't bother taking it further, as my first attempt was proven a waste of time. I considered writing to the owner, who seemed like a nice guy, but I figured this may become another swept-under-the-rug thing. So I'm writing here. Every chaotic thing that happened at Dim T in those 5 months was because of the irresponsibility of Head Management. I don't care if any other staff/managers were incompetent or inappropriate. Head Management is responsible for all conducts and activities in these restaurants, and until they are seriously reevaluated, the chain's management methods will stay unjust, and well, in bad taste.