Geoff Mann has been tending Brownstones topouts for years. As far as I know, every year he prunes a different section of heather.
But I'm sure if you organised a heather removal/bramble chopping day, you'd get a reasonable response.
As for making the long back wall more popular, I think that's going to be down to the guidebook to inspire people. Perhaps we need a long back wall meet sometime - lots of pads and spotters, lots of highball ticking, and lots of good photos for the guidebook.
The other thing that might help is giving some of the routes proper grades. The taller routes are just too tall to be boulder problems for all but the very brave. Give them route grades and they might see new interest. Some abseil/belay stakes at the top would probably also be a good idea if this is the way forward. ...What does everyone else think? I have reservations about changing the atmosphere of the long back wall by encouraging gear and ropes and faffing and all that, but it might be a good way to keep the vegetation down.