help x advise on financial settlement

Hi please if eanyone can advise, my FH in approaching at end of july house is currently on for 650k would hope to recieve 625k ,mortgage is 410k and endowments are 77k i have 3 children 17, boy 13 girl and 7 boy who all need there space i have done my research and i would need 250k to rehouse for myself and children this would prob mean convert garage to bed or achieve a small 4 bed in a respectable area my sol is pushing i get 250k to rehouse ,but this may also mean a call back of where ex still owns percent of which i pay back my little one reaches 18, ex has always had good job who earns loads of money i havent worked since having children and not needing too also having medical condition, we are also hoping for spousal maintenance please could anyone advise on the above and what probability this might be and also what other options that might be available.ps solicitor does not want me to have a mortgge and besides very doubtful i would get one pensions have been sorted equally by an actuarie there are no other monies involved many thanks please help xx