I forget how old it is but it is quite old and never been cleaned to my knowledge.
Ive just had another look at it now dry and where the darker bits are the pile is very thin, compared to the lighter bits. Very very thin. The strands have little black bits (look sort of like blackhead spots) on top of each strand.
It still looks very dirty, but after two applications of warm shockwave and a shot of loads of different spotters, none with an obvious effect, I have given up on it.
I also put down some oxibright quite heavily and heavily diluted (45g to 1 litre of water), agitated, let dwell for half an hour in alcheline enviroment and rinsed. Did not help very much if at all.
Maybe soon I will have to buy a rotary. i still find it hard to believe that a rotary would have helped much with this though!