There was, I believe, an attempt to challenge it (I wasn’t involved, which I regret).
Also, several of us (individually, not collectively) applied to be exempted from the works, as we’d be able to install our own boiler, pipework, radiators etc for a fraction of the price charged by Camden. However, this request was rejected. From looking elsewhere on this forum I have concluded that Camden must have a policy of not allowing leaseholders to exempt themselves from such heating works (presumably because the vast sums we pay contribute significantly to the overall project costs).
I concluded that Camden had closed all the alternative routes and that we were left with no other option than the one they had chosen. I shouldn’t have given up so easily, but too much else was happening in my life at that time (not least trying for 6 months to get leaks fixed and damage made good) to be able to take on Camden over this.