The trainers are Brooks ones from Wiggle, I walked over a wet floor to find out what my footprint looks like and went with the ones they recommended. They certainly feel like they're supporting my foot well. A distinct improvement on running in Woolworths' plimsolls*.
I don't think I'm likely to have any problems overexerting myself.
I'm trying to take smaller steps and roll, rather than bounce. I think one of the reasons that I was so crap at running was that I was doing a slow bounce, which takes considerable effort!
I just don't understand the shin thing - it was fine when jogging but long-strides-fast-walking was painful, like I was jarring my shin bones, and I couldn't work out what it was. If it's just a n00b problem then I will stick to the park until I've built up a bit more.
*Everyone else had Nike GreenFlash, which were (I agree in retrospect) a total waste of money for a girl with growing feet who attended games lessons... infrequently.