So have mousy boring brown hair with some odd grey hairs - if I buy a nice n easy type dye, could I choose dark blonde in the hope it will cover grey and make them look like highlights? Or should I go aa bit darker and opt for caramel?
I''d say always go lighter than you think with box dye, so the dark blonde (or perhaps even a shade lighter). Keep in mind that the colour may not stick to the greys and wash out in a few washes in any case, and stick as close to your natural colour as possible to avoid roots as well as greys.
A light ash brown gives mine a highlit look and was suggested by a hairdresser I do get highlights too but not frequently. About every 6 months because an ashy tint on greys blends it in well To keep the colour you need a non sulphate free shampoo