Hello loramissy, I did this a few years ago, the hairdressers has to do something special to the blonde cos otherwise brown on blonde goes green so under no circumstances should you diy! secondly should be quite easy to go back t blonde as you'd only have to lift the colour, however it will knacker your hair if you keep colouring and bleaching it. Like i said i did this a few years ago and really enjoyed the change although be prepared to fell very different and be reacted to differently if you've been quite blonde. It's weird, i went back to blonde about a eight months or so after and am currently thinking about doing it again! Have fun!