Focus does look very good I must say,but £2300 is strong,plus they do suffer from pump/injector issues also,not in such abundance as the 2.0 l tdci mondeos but it still happens.
Vw or Audi a4 etc would be a fine choice,shouldn't be too silly on price,they really do go on forever in fairness.
Avoid renault,rubbish,pug dervs are good but sadly not much jap about for that price in diesel flavour or that would be where I'd be looking.