from where I start, it's about 20 miles in all, which I run at c. 10 minute mile pace.
I've done that particular run on about 5 occasions in the last three years when training for Paris and London, and which marathons I've done in each of the last two years.
I'll be going back to these routes in January, so maybe we could arrange something then. My training partners then will be Juliet and Donna, who live nearby, and who will also be training for Paris, having trained for London with me last April.