I've got quite long hair and for the past year have had a full head of highlights, so I have a lot of bleach in my hair. I wanted my hair bright red, but it's turned out a dark brown/chestnut colour. How can I now get it brighter. If I put another dye on it such as directions, will it lift with all the bleach underneath?

This is a tricky process and I frankly wouldn't try it at home. It's hard to guess what results you will get if you bleach colored hair - it could come out quite unnatural looking. Often, a professional colorist will strip the color out of your hair, then re-color it how you want it. It can be very hard on your hair to do all this processing, so I wouldn't try it at home - wouldn't want to fry it and have it breaking off or falling out.