my pal and his girlfriend are thinking of buying a house.he has a large deposit available for a downpayment.she has no savings.they would split the mortage 50/50 and bills.by way of example if the deposit was 100,000,and the mortage was 200,000 that would be 300,000 for the house value.if the relationship was to break up,what is the most equal way it could be divided. and should there be some sort of aggrement signed by both parties that would stand up legally.