Marplerambler - As a person who owned a horse and rode frequently in the past, a car driver, a rambler and now first and foremost a mountain biker, I can see that you have typically (for a walker) got upset at the use of mtbikes on bridleways.
Yes there will always be the few who think it's their God given right to behave how they like. This I have found (as Henrietta mentions above) in all users of our countryside.
It will amaze you to know that mtbiking is a popular and huge participant sport in and around Marple and that 90% of us are walkers too (a fair few ride horses). Around this area, mainly up and around the Roman Lakes we all get on and are polite. No mtber is purposely going to go out to kill or injure a rambler or horse rider, or any other user of the countryside.
We live in an overpopulated country and the countryside is for the enjoyment of all. The very fact that people are going out and getting off their backsides to participate in an activity is only a good thing. We must be tolerant of each other.
I have never had a problem out rambling with mtbikers, in fact I would say the majority of grumpy people I come across are walkers. But this is another matter.
Personally I think a new bridleway would be a great thing for Chadkirk. The more horse riders, cyclists and walkers we get out into our beautiful countryside to enjoy it the better. Also out of cars and taking part in activities.