I haven't hiked in the UK. I have hiked in the US. There is nothing worse than a bunch of trail bikes, mountain bikes, ATVs, or a four wheel drive vehicle come roaring down the path (either from behind or from the front) unless it's loud music cutting the fabric of the silence.

Don't get in a twist. I own a four wheel drive vehicle; it's often needed here where I live, especially in winter. I don't drive it up a trail system and, were I still hunting, I would take it as far as the road (and my skill) permitted and then walk. How else can you actually hunt and still call yourself a hunter?

But I no longer hunt; I can get my food from other sources (and folks a lot younger than I). But have spent my fair share of time back in them thar hills I can say that there is no need for loud engines, loud music (use earbuds if you must!), and loud talking and laughing. The few times I rode an ATV it was well-muffled and we moved rather quietly.

My feelings are mixed: an ATV can be useful (ranchers around here use them, as do search-and-rescue units, law enforcement, and others). I see no place for "dirt bikes" and "mountain bikes" unless they stay on marked trails and angles at least 60 degrees from the fall line (to prevent erosion). Better, give them their own place.

Horses...I don't know enough to comment.