I had my blonde highlighted hair dyed a mid-brown colour at the hairdresser a couple of weeks ago (Matrix Coloursync 7M I think... ) it came out with warm tones due to the natural warmth to my hair apparently.

I love it, but can't afford to keep going to the hairdresser to get it redone every 2 months so was wondering if anyone knows which L'Oreal (or other brand) semi-permanent home dye is a similar colour?

Also, will it matter using a different dye over it when it starts to fade? I know permanent colours build up over time and get darker, is it the same with demis?

Thanks!