Advice for dying a second time

Was your hair naturally dark brown?

When you redye, ONLY do the roots. Never dye over the rest, it's so damaging. Then use a true semi, like the adore range or special effects (both sold on beeunique.co.uk) to top up the red. You can mix a pink red and an orange red to make a truer red. I promise you that you will have better results this way and save your hair from a lot of damage 🙂

Was your hair naturally dark brown?

When you reduce, ONLY do the roots. Never dye over the rest, it's so damaging. Then use a true semi, like the adore range or special effects (both sold on beeunique.co.uk) to top up the red. You can mix a pink red and an orange red to make a truer red. I promise you that you will have better results this way and save your hair from a lot of damage 🙂

My hair is naturally dark brown, but has been dyed a lot (although never gone light)

I would never have thought to use a semi over the rest, won't it end up being a different colour to the roots? Hair colouring is so confusing!

It will be more even this way than if you apply a high-lift dye all over.

Right, so the hair that is darker was hair that had been dyed before? If so, then that's why it's darker. Hi lift dyes are only meant to  lift natural pigment in hair. They aren't designed to lift others dyes and so do a bad job of that. What you should have done before using the affine would be to use a colour remover to get rid of as much of the old dyes as possible. You could still do that.

And yes, dying over the red with a direct dye will give a more even result 🙂

So I use the previous colour on my roots then a semi permanent on the rest? Do I do them at the same time?!

You would use the high lift on just the roots, shampoo, then apply your semi dye all over.