The cambelt is a critical part of any engine so we would strongly recommend having this work carried out. You do have the option to sell the vehicle if you would rather not have this work carried out, but you may wish to try an independent Ford specialist who will likely be able to carry out this work at a reduced cost. The dashboard does not give a specific warning if there is an issue with this component, and typically if there is a cambelt problem catastrophic damage can be caused before there is even any signs that there is a problem.