Sounds like they may have worked it all out, unheated indoor parks are often colder in winter than the outside temp, corby has been colder inside than out the few times I've been.
Not sure we will see the mesh thing up north as a lot of our rain in winter is horizontal accompanied by a 80mph wind
We have a nice park at East Kilbride which is in a newly built sports complex which is open 7 days all year and fully heated. (and light)