Thanks all for the advice. The bad salon experience happened around a year ago, and it was the actual colour, a sort of weird mousy brown, which was the problem, although the condition of my hair deteriorated too. I really wasn't that impressed by the hairdresser so decided to just not go back.
Prior to that I was using a different salon until the hairdresser moved away, however I was going every 3 weeks and the hairdresser told me that it was because my hair grew really fast, and she had another client who was having to do the same. I'm now wondering if it was the product she was using, or maybe the colour was wrong
She also used to do all of my hair, so the roots were mid brown but the rest of my hair got darker because of the amount of colour she put on!
My hair used to be mid brown and is now light grey, so I'm using a mid brown dye, which is the same colour as the first hairdresser but I think I need to go for a light brown or dark blonde so will need to find another hairdresser, and it's not something I look forward to.