mortgage free or carry on living near support?

pinkfemme1

I'd love some advice about my situation.
I'm a single mum with 2 school age kids, who I have full time
My current yearly salary is 50k, I get child benefit and some hit and miss child maintenance of around £150 a month (he is self-employed, it's impossible to challenge that)
After taxes and pension contributions I have around £3100 a month
£140 k left to pay on mortgage, house worth around £300k, so around £160k in equity. Where I live (Leeds) I could in theory get a house for that price (160k), but it would mean moving to a much less desirable area, smaller house, away from support network and kids' school. 
However I currently pay almost £900 in mortgage a month and then
council tax £120
electricity and gas £230
phone £17
car inc £65
petrol £100
food £300-400
cat food, vet etc. £100
kids afterschool activities £95
water £50
tv licence £14
life insurance £73
kids ISA £50
internet £26
and then there are other costs like repairs, car tax, professional membership fee, other things that seem to come up a lot. 
I never seem to have any money left at the end of the month, I literary have around £200 oin savings, can't afford to take kids on holidays or anything.
I've also started a side hustle and had to buy a few things for that before it makes money, but this just means more work. I use my house for this. 

I'm a bit burnt out with it all and not sure what's best to do. Any advice would be welcome!!

pinkfemme1

Just to add 
no family support
ex doesn’t want to have kids overnight 

beanielou

No middle ground?  ie move to somewhere cheaper & still have a small mortgage which would reduce your mortgage outgoings?