Hi Gav,
Ordinarily, i would agree that it could be intermitent claudication - narrowed arteries, usually the femoral artery but you mention that there is tingling in the back and buttock area - this is usually not a sign of femoral artery claudication.
It is possible that there is some sciatic / back involvement.
It is difficult to diagnose on such limited information. Obviously you aren't a physio so if you could answer the following questions, it might help us physios to help you!
1. Where exactly is the pain and altered sensation?
2. When you rest, do you stretch or just sit down and the movement comes back?
3. Have you had back pain before in the past?
4. Do you take any medication?
5. Do you notice it at any other time? i.e. apart from running around?
6. What happens when you bend over, lean back, twist etc?
7. Do you think you have "tight" muscles in general?
Thanks!