Good toy car shops around Bristol/Gloucester/Chepstow area?

[sosidge]

I'll be going down to see my parents next weekend, just so happens that it is also my birthday and they would like to buy me something for my toy cars (I will be 33!).

They live between Chepstow and Gloucester and we will also be going to Bristol - so what are the good walk-in model shops round that part of the world, ones that will have a good selection of toy car stuff on the shelf that they can buy for me there and then?