I've just completed the London Marathon and am now at a stage where I want to keep running and bring down my mileage gradually rather than just stop. Are there any plans to follow for this?
I think that taking a break for weeks is a bit radical for non-elite runners. What I see others do in my track & field club (and did myself, after my 2 marathons so far) is rest for 2 or 3 days, and then see if you are able to do some jogging or recovery training. Then, after a week or so, you can slowly get back to a regular training schedule. How long it will take completely depends on how you feel. Don't be afraid to break off a training session if you are feeling tired or light in the head. A marathon is tough on the body and you need to take care of your body afterwards.
I'm backed up by this site, which has a more specific training plan, but the giste of it is that you need to keep listening to your body, and act on it. There is no sure way to recover from a marathon, not even for the same person. Every race is different and sometimes you feel very tired, other times you feel on top of the world, and are able to run your next marathon two weeks later. There is no way of telling what will be the case. Just take things as they develop and enjoy the recovery process, because it's really marvelous that your body can recuperate so rapidly.
Firstly congratulations on your marathon, and I hope you are pleased with your result.
What I'm going to suggest is hard for marathon runners to do, but honestly it is the best thing to prevent injury and help you recover quickly.
The best thing for you to do, is to stop running for 2-3 weeks.
This is what people like Paula Radcliffe do, and we all know how hard she trains.
Instead of running, you should walk or swim. This will help pump the blood round your body to speed the recovery process without taxing already sore muscles.
So many people I see get injured in that first month after a marathon, because they are on a marathon high, and continue to pound out the miles. Enjoy your rest, spend more time with family and friends, then return to running slowly.