It is simple to wade through the red tape it is just the associated cost and initial cash flow.
If you are trying to do it whilst working so a couple of tours a year then I would suggest that the initial costs you will need to meet will make the tour price prohibative, if you aim to make a profit, especially if you don't already own the necessary support vehicle and equipment.
When talking about doing it as a soul method of earning a living consider how much income you need, and how many tours you think you could run a year.
For example soley running LEJoG trips, even at 100miles a day its a 10day tour so a 2 week turnaround. The weather will preclude at least 5 months of the year for your clientele if not you so a max of say 14 trips a year. You need to earn say 21k a year before tax so each trip needs to clear £1500. On top of that £1500 it also as to cover your expenses (hotel/camping/van/petrol) for each trip 2000 @ 25mpg x £6 = £480 10 x B&B/ camping +food £40? =£400, van depreciation + insurance (for business and carrying fee paying passengers) £2k+ a year / 14 say £150 a trip, so each trip you do as to have a clear profit of £2600+ and that is before public liability/ promotion/ web hosting/ advertising etc etc so lets say £3000 per trip.
Even if you are optamistic and say 10 people on every trip then that is £300 every punter as to pay over and above what it would cost them to DIY. So for a couple camping that is an additional £600 and that's without you taking the proverbial!!
I wish you the best of luck and might be teaching you to suck eggs, but I spent a lot of energy and time looking into setting up a car tours venture in a similar vein and came to the conclusion I couldn't do it cheap enough to appeal to the average person.
I would suggest as a small operator the only way you could make it work would be to aim as niche as possible ie 5* hotels every night and a clientele who can afford to pay the premium of your mark up when divided between a small group, wether this market is already saturated or can be undercut only research can tell