Fortunately for me, the residency period for settlement/permanent residency/indefinite leave to remain (ILR), was not extended beyond five years. I can apply for ILR as soon as I qualify, which is well before my current visa expires. I am lucky. I'm certain others are not.
I decided to phone up the UK Border Agency to check whether or not I could apply for ILR as the unmarried partner of a British national. I can't, because my visa is for work and not for shacking up with an Englishman.
After I hung up, I realised that if, the last time I'd renewed my visa, I'd applied to be the unmarried partner of a UK citizen instead of a highly skilled migrant, I would have qualified after two years of living with him. Which means that I could have submitted my application this June instead of this October.
Oh, immigration rules. Your logic, it is, well. Not.