Happy to give my view for what it’s worth, but all the best with whatever you decide. My background is a lawyer, and a reasonable amount of experience with mortgage/house prices etc. (To be clear the below is all speculative advice and not legal/financial advice).
To give my full opinion, I’d like to mention some of the surrounding factors.
Firstly, your current job is stable and has a good salary, if the new job does not work out then you have the dilemma of finding something new very quickly, otherwise you risk having to start to eat into your house deposit whilst you job hunt - not ideal, but it sounds like you’re good at what you do and should be able To source a new job fairly quickly.
Secondly, the housing market is heavily expected to decline in the coming months. Unemployment will reach an all time high, demand and eligibility for mortgages/properties will decline and the market will suffer. Only short term, but it will. This is further strengthened by the fact that the SDLT holiday ends 31st March. You may therefore find that if you were to wait another 6 months or so before buying you not only have a bigger deposit, the CCJ is even older (and other credit factors probably also improved) and the price of what you are looking for may well have come down. Even the government are anticipating an 8% decrease in average house prices but in real terms it probably won’t be this bad but maybe consider a 3-4% saving on the purchase price. The other factors above would also suggest you would become more favourable to a lender and perhaps get a better rate which over the course of 25 years on that kind of money could be a big saving in itself.
Umtimately, like others have said following your gut is always a good instinct to follow and you have to do what is right for you and your family.
I think what I would be looking to do is take the new job, but put off the house purchase for 6 months. During that time your deposit will at worst stay the same, but you may earn a payrise with the new company given the scope for progression and then when you do buy might find yourself in a much stronger position.
There’s of course some number crunching you need to do regarding the lower commute, but increase childcare cost and a lesser salary to begin with which only you can assess.
Hope this helps and all the best with whatever you decide.