As with previous Enigma events, held at Caldecotte Lakes at Milton Keynes. One small loop, followed by 7 laps of the lakes. Mostly tarmac paths, however it is possible to run on the grass alongside the path for at least half of each lap. Not recommended in the last event when the grass was frozen harder than the tarmac, but, in normal weather, well worth doing if you've got another marathon the next day! Being able to have your own food and drinks at each lap helps as well, so lots of flat Coke, some sports drink, a couple of gels, a couple of hot cross buns (it is Easter!) and some chocolates kept me well fuelled for this and the next day.
My run: Had a twinge in the ankle at 18miles, so back off for the last few laps, walked and chatted with someone I'd lapped from mile 24 to 25, then jogged the last bit. Time: one minute off my PB, with a 4:46:31.