please hold your horses, let me tell you a story
around 8 people that I know where they hold a similar business to mine have been shafted when selling their round. One story was this guys business was earning him £2,000 per month, he had a mortgage and kids, he decided to go on holiday and let his friend look after his work for him, when the guy got back from holiday he told his friend that he was taking over and thanks, his friend just said no and threatened him, the guy has now lost his house.
Another story was that a guy was selling his business exactly the same way as i was the interested party told him 50% up front and then another 50% at the end once it was worked, the guy agreed and he got paid his first installment, then the other guy simply said that most of the round had cancelled and that he was not getting hi last installment, when he went round to his customers houses to find out if they had really cancelled, it turned out to be a load of rubbish and all the customers were saying was 'tough luck mate i would come back but all i want is my windows to be cleaned'. So the guy sold his £6,000 per month business for £9,000.
The moral of this story is you cannot trust anyone to hand over the next 50% installment, why should they after all they have all your customers details. I wouldn't even like to show them my work as they could go over my round and under cut me.
At the end of the day I can show the round working, I can give them a database with all the house addresses and contact details. I have even taken them to my home to meet me. I HAVEN'T SPENT YEARS OF MY LIFE BUILDING UP A SOLID BUSINESS TO GET SHAFTED AT THE END OF IT, I BOUGHT ROUNDS UP FRONT AND IT WORKED OUT FINE