This is what I would do. But rental property is in very short supply just at the moment. Or house share with family, possibly take in a lodger (difficult with small children, I imagine).
Yoi could also go interest only to give you some breathing space while you have childcare bills, but the thing will have to be paid eventually. (Or not. Maybe interest only will become the norm, and mortgages will become a sort of permanent rental arrangement?)
There’s extending the term, depending on how long you’ve had a mortgage, but it’s still a stop gap.
You could consider a mortgage holiday, but honestly, I don’t think this is going to be short term. The base rate is going to go up to around 8% and perhaps as high as 10%, for some months before settling at 5/6%. Just like it always has. I imagine there are great many people who have never seen that. I’m 44 and bought a house at 24. I earned 15k, the mortgage was around 60k and the house (big 4 bed terrace in a nice city) was around 90k. My payments were about £600 a month. On a 60k mortgage. And all of that was entirely typical.
Rates have been artificially low for a very long time. People under about forty haven’t ever seen these interest rates before (in their house-owning years which is when you pay attention) and can be complexly forgiven for thinking the low rates we’ve had are normal. They’ve also been allowed and encouraged to borrow much higher amounts for more expensive houses and everyone has complained bitterly about affordability and stress testing, because it was so much more expensive than rent. Sadly, those days are gone. If we are very lucky, and have a change of government, we might get low interest rates back after a high peak and then a long slow rise over a number of years to ease us back to normal, but I’m not an economist and don’t know what the implications of that might be. It might not be possible, but for ordinary people, it’s the best possible outcome I can see.
Oh, and don’t vote conservative. The government don’t care where ordinary people find the money. They couldn’t give a monkeys if people lose houses. In fact, they’d love them to. It’s a smash and grab, so the super-rich can acquire even more limited assets, cheaply and rent them back to you a fat profit. Cheers Liz.