In my view, a Rallye really needs to be kept indoors due to the propensity for corrosion - ours had big main spar problems and this seems an Achilles' Heel for the type.
We had ours based at Denham and it would be good to see another around the place again, but hangarage there is now relatively expensive. we now keep our PA28 out-of-doors for a much more reasonable sum.
Flying restrictions? Well, for the convenience of being co close to London, operating within the Heathrow Zone isn't as restrictive as you might think. You can only enter and exit via the north, unless you get a SVFR then you can use the western part of the zone if they can fit you in. I guess we get used to it. The real restrtiction for flying training is having to go some distance to get enough height for the stalling etc exercises, but that applies equally to the other close-in airfields, too.
Cheers,
TheOddOne