Upon reading your advice above, it now confirms why I thought I struggled this morning!
I went and attempted the 5/15/10 but it just wasn't going to happen...
1 06:38 (too conservatively perhaps)
2 04:41 too hard!
3 05:31 nothing left!
4 05:39 then I quit and walked the 10 min warm down home.
I changed my planned route after I set off because of how dark it was and didn't want to risk injury on the uneven ground off road. So from now on will stick to lite paths. There is a good 800m looped "island" so I can lap this as many times as I like without having to stop for traffic or people at that time in the morning, it is flat also- bonus.
Obviously not pushing myself in the first KM at trying to conserve as much as possible the the paced 15min. Went too hard and payed the price. I will get better at judging pace as I run more. Stretches tonight and tomorrow and we will see what Wednesday brings. Hopefully the legs will have a bit more in them by then!
Nevermind, onwards we go! Lesson learned.