Rob,
So you don't like MK - that is clear - but the hazards you have encountered there are just as present at both Hillingdon and Eastway. Rather than misleading people into thinking it is just at MK it must be made clear that they also happen at favoured venues and are likely anywhere that has public access. (For the record I have never personally interfaced with dog-mess at any of them!)
I have run in BC races at Hillingdon very many times over the years during which I have seen loose dogs, loose pedestrians, non competing cycles and unauthorised motocrossers getting in the way of racers. Also, twice, I have encountered ASBO candidates throwing rocks and other missiles at passing racers - along the back straight and on the far side near where all the buses gather. These areas need to be watched as there is some sort of access about halfway along the backstraight where the little darlings can get in unseen by participants / organisers.
Eastway is barely relevant with its anticipated bulldozing but the backstraight there also often has loose dogs and people. Even, once, encountered a woman pushing a shopping trolley up it as I approached at 30+ mph!
Point is don't make people think MK is unsafe but other places are - cos they aren't much better. Only proper motor racing facities will achieve that. If there is notable "feedback" on a venue it would be a polite to at least discuss it with the organiser rather than unilaterally exclude a regular event without even mentioning it to them. Worse here is I was led to believe it was on so it is booked.
If the committee wants to make secretive unilateral decisions like this perhaps they would like to unilaterally organise all the events as well while the rest of us shut up, pay up, and turn up to race like good little children.