It rather assumes you could enforce them. Those rights will be great against a responsible outfit. But if the data is exposed in a breach, or if the outfit goes rogue (or if a future government decides to change the law and sell your data, as, by the way, the previous Conservatives tried to do), then you're lost.
I thought you may mean that the legal rights provide protection, so one need not worry until deidentification or detachment. Maybe your emphasis was same.
But for clarity, I think we need to worry long before deidentification and detachment — basically the Trusts are not to be trusted, and our legal rights will vanish in a heartbeat.
