Neil, do you have any sharp shooting pains down the back of your leg, or any where else. Having suffered with piriformis I know it's not nice. When I'd get up of the couch I'd get a sharp shooting pain down the back of my leg. Plus the lower back problems it caused.
Blue Steve, the Garstang half is only 2 weeks before the marathon then? That's a bit to close for me. The Warrington half is three weeks out so should be no problem racing it.