Despite the cold and slight fog/mist in my park I did it. First 5 mins was a bit tough because of the cold though I soon warmed up and from then on it was challenging but, and I know this sounds weird, it was great fun too. I paced myself on distance rather than the clock which is easy as my park circuit is 1km, and actually managed to run for 4.5km in that 25 minutes and I feel amazing. Don't want to get over confident, but I am sure I could have run on for another 5 minutes if Laura had told me to. Maybe fortunately, she didn't.
Anyone about to do it, go for it. It sounds scary but it's doable if you've done all the other runs. I'm celebrating on my no carb diet with a huge bowl of porridge and crunchy nut cereal, dried fruits and almond milk. Sorry Dr Dukan, but I'm worth it