Livre d'Or

I use L'Oreal and it gets my hair pretty bright without bleaching - I think our hair colours are reasonably similar. It is permanent though, so you'd have to dye over it to go back to your natural colour, but as such it stays vibrant a lot longer than the semi-perm ones, and is about the only brand that does permanent purple as far as I can tell. I'm also not entirely certain whether they entirely avoid animal testing, which I imagine is something you care about more than I do.

If I'm dying my own hair I just slap it on any old how, but with hair as long as yours, it's probably a lot easier to get someone else to do it for you. I'd be happy to if we're going to be in the same town at a suitable time. (I used to work as an assistant in a hairdressers as a teenager, and although I never actually dyed hair professionally, I picked up a fair bit).

If someone else is doing it, they'll have a much easier time of it with a proper hair dye brush than using the applicator nozzle. The method I use is to part the hair into four quarters, and apply the dye to the first inch or so of hair along both partings, then work diagonally through each quarter, again applying dye to the first inch or so of hair. Once you've got full coverage on the roots, start again at the centre, this time applying dye along the full lenght of hair; once it's all applied, massage through the length briefly, wind it up to keep it out of the way, and cover with the plastic cap supplied (or clingfilm) whilst you wait. If your hair is fairly robust, then it's fine to leave it on for a bit longer than the guildelines say (wash it off immediately if it starts to sting or burn, but don't worry about gentle tingling or itching).