This is a long marriage, so marital assets should be split evenly. Although there is one child, as she is about to become adult at 18, I suspect that one could consider that there are (almost) no dependants, certainly that could be the position at the end of her secondary education.
For the first mtg, it may be useful to listen to your stbx's proposal, and then say you would like ~ 50:50 split.
House could be sold, so both parties have 50% of equity towards rehousing. Or can she raise enough to buy you out of the house - ie at least £80k
Additionally, you are entitled to ~ 1/3 of her pension so that the pensions are equalised. Alternatively she could keep all her pension and offer you a larger share of the equity.
my ex has put the house up for sale already to which i agreed .i am not forceing the sale as would prefer to wait till daughter is 18 in 12 months time.hope ive done the right thing by agreeing to the sale now ?