I would expect that the claim form will ask questions about your income while you were allegedly off sick from the first job. The claim form is a legal document so you would not be advised to lie. I would think - though I may be wrong - that (depending on the terms of the policy) they might pay you sick pay until you started the other job in September. More importantly IMO, did you still claim state sick pay after you started the other job? That also could be seen as fraudulent if you didn't tell the benefits office. I don't know what I'd do if I were in your position. It also occurs to me don't you have any sort of sickness cover relating to your mortgage, so you could have claimed off that when you were signed off sick, so your repayments were covered and you didn't have to struggle quite so much?