Dave, I have to agree with everything you have said, it all makes common sense. Even the Poll Tax would have been fair, although not easily enforceable unlike Council Tax
For example water rates, you can use as much as you like such as washing the car, watering the garden etc etc so long as you don't have a water meter, then you have to pay for what you use. Perhaps it's time that all houses, new and old had to have a water meter installed to make the system fairer
My situation is very similar to yours, even to the fact that I have lived in my home for 38 years.
About 2005 the Inland Revenue Valuation Office rebanded my house from F to G without any notice. That office then sent a Valuation Officer to look at my house and he was quite unpleasant to my wife and fortunately for him I was out at work. I made an appeal against the revaluatuon and the procedure is not easy as you have found out to your cost
Anyway I phoned the Valuation Office up and spoke to the person who called at my house and when I asked to have a meeting with him at his office which at the time was only 100 yards away from my office he refused my request
Instead he said that he would call again at my house and have another look inside it and at that point I said to him that if he sets one foot inside my property I would physically throw him out.
Anyway after I supplied more details of the property to the Valuation Office my Tax banding was returned back to F
The system is grossly unfair and I have every sympathy with you on what you are having to go through. The Wales Office is considering a new revaluation although they had one in 2003 and that may be fair, but only if England has one as England have avoided having one in the past for whatever reason