I recently treated a carpet stain with some washing-up liquid. To start the results were great, but now there is an even larger mark on the carpet?

Don't ever use any cleaning agents such as washing-up liquids, soaps or other detergents recommended for general household use, washing the car or your hair. Although they may clean your carpet satisfactorily, they will almost certainly cause problems such as rapid re-soiling, colour bleeding or other damage to the pile or backing of the carpet. Always use a WoolSafe Approved cleaning agent.