(Your home address)

Date:………..
(Creditor Address)

Dear Sir/Madam
Without Prejudice
Account No: …………………………
I/we write acting as a third party with reference to the money which you are claiming on the above account.
I/we have attached a letter signed by (debtors details) explaining the situation and giving me/us authorization to discuss their account. 
I am/we are fully aware that (name of the debtor) is unable to offer to pay the money which they owe in full.
However, acting as a third party on behalf of (name of the debtor) I/we can raise £ (put the amount which you can afford to pay) and I/we want to offer this as an ex-gratia payment in full and final settlement of the account. This offer is made on the clear understanding that, if accepted, neither you nor any associate company will take any other action to enforce or pursue this debt in any way whatsoever and that (name of the debtor) will be released from any liability.
I/we also request that, if accepted, you will make an entry on a credit reference agency file relating to the above account as having been paid and the account closed.
Payment can be made within (put the number of days or weeks within which you will pay) of receiving your written agreement of this offer and method of payment.
I/we look forward to receiving your reply.
Yours faithfully

(Your signature/s)