I had my hair dyed in a hairdressers for the first time this time last year - I had dark reds, few copper highlights and browns, this has now faded and my natural hair colour has come through, I want to dye my hair again (to match my normal hair colour which is brown) but using a box hair dye - do you think this will be ok? Thanks in advance :)
Go for it. The old colour would have long faded by now, and there won't be a 'risk' of it reacting/not taking, if that's what you're worried about.
As above, I would go for two boxes if you have long hair, as you may find one starts to become patchy.
I dye my hair at home all the time, it's shoulder length and just on the verge of needing a second box, if you're hairs long, you'll definitely need two.