The Land Registry thinks it belongs to the Elveden Estate, at least the part along Seven Tree Road.

I don't actually know what happens if it's under TTRO. I think misusing a RoW is considered a trespass, but breaking a TRO is probably something different.

I've sent a last-ditch request to SCC (and copied my message to CycleScape). I gave them your imgur link; I hope that's Ok!

My next step will probably be to involve the local MP, simply because I don't know what else to try.