Still a lot of terrible advice being given on this thread, especially claim that this is a case where there will be a departure from 50/50. If there is, it will be 55/45 on the house equity only at best (and 50/50 on the pensions, provided they all accrued after marriage).
The big mistake everyone is making is basing their assumptions on gross incomes actually earned, which is completely and utterly the wrong way to look at it. What people should be considering is net incomes based on earning capacity.
First of all, either now or in the very near future the OP will be expected to go back to work full time where we might impute a gross income of £25k. She is also eligible for universal credit, child benefit and child maintenance. On the new imputed income that will mean £1,750 in net earnings, £337 in universal credit, £241 in child benefit and £633 in child maintenance to make a total net income of £2,961.
In contrast, the ex-husband will earn net £3,654 minus the child maintenance of £633. So he will be on £3,021 a month, a £60 difference with the OP. With the children 3 nights a week with him, there is absolutely no question of spousal maintenance with such a tiny difference in net monthly income. That was the first piece of crap advice that we can discount.
Now, the Mesher Order might have been decent advice a year ago but is now the second piece of crap advice dished out here. Interest rates have gone through the roof and before this kind of advice is dished out, the OP will need to know if she can afford the mortgage on her own. As a rule of thumb, a £200k mortgage costs around £1.2k and will probably be more expensive by the end of the year. The OP's ex won't be able to help her as he will have his own housing costs for three children three nights a week and that will mean rent that wipes out nearly half his net income after CM. It seems likely the house will have to be sold and shared ownership might become an option.
The only good piece of advice offered is to split the pensions (or, rather, the matrimonial pensions. Anything before that is not up for grabs). Everything else is bollocks.