If you want to pay £0, ignore every offer of settlement that they will try. They have been known to go sown to as little as £5, as though the person responsible for the case is desperate for some minuscule amount of commission.
We have been known to string them along by pretending to hum and hah as though we are considering it, but never by phone or email. Only by text. Can be quite good fun. A bit like deliberately engaging with a Nigerian prince who wants to give you £10,000,000 for safekeeping!