I did the 34k instead of the HM (because I'd got the date of the HM wrong!), two weeks out from the marathon. I did it as six laps of a mostly flat 5.3k route (with a bit extra to get there from home). The idea was to simulate race conditions my having a cache of water bottles that I dipped into on each lap. I ran 5 laps at a steady 5:10 kms and then did the last lap at 4:45. It felt quite comfortable at the time and was my last hard run before race day.
It seems everyone is always doing insufficient training or too much training. Or both.
Well, I can only conclude that wearing the shirt early is actually lucky. Logistically, this race could not have gone better. I didn't really know where I was going but somehow found my way to the best car-park, right next to the start. Then I nipped through a barrier thinking it was the way to the start area and found myself 'backstage' and face to face with the only portaloo in the district without a 400m long queue.
I went through half way in about 1:44 and then merrily bashed out 4:55 kms for much of the second half, picking off slowing runners ll the way. Eventually I got worn down by the hills on a lumpy course and struggled a bit over the last 5k - lost some of those places and saw 3:30 slip away. Came in at 3:33 - which is still a 24 min PB so happy days.
On balance I think that plan was the right one even if it didn't quite come off. If I'd paced for, say, 3:20 it would certainly have ended in doom.
In the build up to this race I did four 20M+ training runs. On the last one did 34km at about target pace, with the last 5km faster. None of this seems enough to prepare you for the full marathon. It's mad, really.
So in conclusion, over-reach at your peril.
[please excuse the mixture of imperial and metric measurements. It's an ugly habit, I know]
I ran a marathon this weekend. Aiming for 3:30. The 3:30 pacer flew off at the start and I didn't see him again until mile 15, when I was a minute or two ahead of schedule. Even then it was only because he'd stopped and was messing with his shoe. Passed him but never saw him again although I finished in 3:33 .