Hey people,it's as formal as the people involved have time to make it.
All the rides on the SDD are ratified in one way or another, everyone who has had a go has googled "South Downs Double", found the website, and got in contact with someone or another.
Rides are seen off and back by other riders and normally local riders and supportes will pop out onto the trail to watch riders coming past. Often the rider will carry a GPS logger too, to prove that they did it too.
For my Singlespeed Double ride I sent my schedule to local riders, phoned in at the start finish and turn and was joined by KMP rider Lea, who turned up unannounced and rode behind me for a chunk (so as not to interfere with my rides or the gates).
If you're going to go that fast, chances are that people will have heard of you, and that you'll be in contact with fast people or maybe sponsors, who will get the word spread to make sure the ride can be ratified.
Oh, and as there's no cash, no podium, just yourself to beat, these are quite personnal rides, so I really can't believe anyone who had enough of a love of cycling to be out enough to get record threatening times, would even have the thought of cheating cross their mind!
However, for the SDD, the website is, as it says up there: http://www.southdownsdouble.net/
It's all still quite a new thing really. For the Pennine Bridleway, which has been completed successfully in one hit by just Steve Heading and Rob Lee, the finish times are 21:39 & 26:43, impressive stuff, as this is much more intimidating terrain and far more isolated in places than the SDW should it go a bit wrong.
The SDD website is a great resource, and helped me enormously in my preparation