YANBU at all.
My p/t wages + small pension come to around £15k pre-deductions. I live alone and have no mortgage or other debts, but just my fixed outgoings (c/tax, utilities, insurances, road tax) come to around £350 a month.
On paper, it should be easily manageable, but every month there seems to be a big outlay on one thing or another (last month my tv died, the month before I needed 2 new tyres, new glasses a couple of months ago). I'm far from skint, and can afford regular haircuts, wine and stuff like that, but there really isn't a huge amount spare.
I get my state pension in August, but I don't think I'll be able to comfortably afford to stop work until I can move to a cheaper area. I could survive on it, but I'd be perpetually anxious about the car or the washing machine packing up.
£25k for a family sounds really tight to me, although if that income is equally earned, there'd be no tax to pay. But rent alone could easily account for £1,000 a month. And children are so expensive. The buggers will insist on growing, ffs.