never tried c&d but they seem decent. my suggestions on the rest:
shoes: do not skimp on these. crockett & jones, about £370
shirts: tm lewin, charles tyrwhitt, they seem to be on permanent sale, around £40 each?
ties: drakes sale just begun, have a look at their website, or there is a factory outlet in islington somewhere. will be around £70 each i think.
based on this, you can work backwards to get the appropriate suit budget.