Amos,

The best organisation to get involved with is the Trail Riders Fellowship – http://www.trf.org.uk/ They are a national body who campaign to keep rights of way open to motorcycles, and also organise group ride outs in your local area. Some of them also compete in enduros, so will be able to give you advice on getting started! There is also an online forum on the website too.

As long as you ride sensibly with a well silenced bike, you should be ok. Stop / switch off your engine for horses though. I started out mountain biking and then decided to do motorbike trail riding as well, so that I could get out and explore trails further away from where I live. Its all about getting out in the countryside and having fun, whether on an MTB, trail motorbike or horse!

Oliver