On the summery screen have a dial going up to 100% to show how much of the FF has been completed/or at least had some information input.
I realise this will require all sections of the fact find to have a "yes" or "no" tick box, which would be helpful anyway. It has already been suggested for example to have "no" toggle for dependants and credit history, so the system can see that the questions have not just been missed.