I'm in for Manchester too, but I'm hoping to hold at about week 6 to 8 of 16 level through the winter, so I'm not scheduling the training programme in quite yet.
When the time comes, I'll be using the Garmin level II heart-rate based plan provided by fullpotential which I believe is based on Daniels or P&D (not sure). This calls for 5 sessions a week. In the other two days I run easy to keep a streak going
I don't take a rest in the last few years, but I don't train as hard. Normally I train for marathons and when there aren't any I scale back a bit. Right now I'm repeating week 6 and 8 of the programme I use, but that means there is still some high intensity and a sunday long run. I'm beginning to think the long run in particular is a bit too much for maintenance. But I wouldn't stop totally as some fitness disappears quite quickly.