There is no single answer to your question as decisions like this are based on potential recovery as estimated by the CC company. You are paying 1,800 per year so a proposal to pay say €5,000 in F&FS may get their attention. Make sure the letter identifies that €5k is the maximum figure you can come up with an not a negotiating ploy. Ideally state that a relative is helping you out by giving you a gift only if the offer is accepted.
It may be a white lie but will give you a realistic chance of acceptance. Also all financial institutions tend to be extremely slow at reverting on settlement offers. If you don't receive a reply within a month consider stopping the 150 payments in order to grab their attention!!