I've managed to get as far as the end of week 4 (amazed myself - I'm 56 year and never been running before!) using my Hi Tec Silver Shadows, but I reckon it's time for a gait analysis and some proper running shoes.
The Hi Tecs are comfortable, and seem to work pretty well on the surface I run on: round the edge of a grassy field which slopes gently by about 20m from bottom to top. But after W4 R3 I've noticed the fronts of both shins are a bit sore, from the ankle up to about a third of the way to the knee.
There seem to be 3 places in Exeter that do gait analysis: Ironbridge Runner; Sweatshop and Runnersneed. I'd be very grateful if anyone has experience of these (or anywhere else I've missed)