Last Saturday I came to Gloucester and went to the park off Horton Rd/Barnwood Rd, Gloucester. There's a kids play area there that is surrounded by a fence made of wooden posts that stand 3-4ft high, they vary in size and height as they're made from branches/trees. As many of these posts have got lost it now makes quite a challenging and enjoyable precision run.
p.s. I'm afraid I don't know the name of the park, but it's just by Gloucester Old Boys RFC, so google them for a map.