@Jonny_Wright Thank you for your post. I have seen the video and posted it up here previously.
You say they take bike life seriously. Why are they riding motocross bikes on the road. Yes you can convert them and run a daylight MOT but they still need plates. No plates, no daylight MOT no insurance. So they are riding on the road illegally. They crash into Mrs Miggins from number 10 and what is the outcome?
I cant ride anymore because of a drunk driver. I loved riding, I worked a long long time to be able to afford my bike and paid a lot of money to insure it in SE London. Why dont they?
You mention finding spots that are not busy, the South Circular is quite busy. As for the American version, really! It is a bunch of people getting together in a group and feeling strength in numbers so doing what they want. I am sure you have Googled their sites, do they look like they are riding within the law?
The place for an MX bike, an MX track.