I'd suggest that rather than hooking up with a stranger you find on the internet, a running club might be a better idea?
They are not all full of super-fast racing snakes, many will have beginners' groups, and it will be safer than meeting up with random strangers.
Also, you won't be relying on one or two people to show up each time.
Have a look at the Serpentine running club, or look on the England Athletics website for clubs near you.