Sorry to add to the gloomy posts but your chances of finding work are almost zero.
As someone has said, you can trip over plasterers, plumbers, people who will 'turn my hand to anything' (I would prefer a qualified tradesperson not a Jack-of-All-Trades to work on my property as would most people
) here in Spain, certainly on this part of the coast.
Add to that the fact that British 'tradesmen' have a poor reputation here as many who claim to be mechanics, plasterers, plumbers etc. have no qualification and no real skill.
You would have problems bringing your car or van here, if it is RHD on British plates as after a period of residence you will be driving illegally. You cannot drive a UK-plated sign-painted vehicle here either.
There is huge unemployment in Spain -almost 25% as opposed to 8% in the UK. It's over 30% in some parts of the Costa del Sol. As someone has pointed out, you would not qualify for free healthcare until you had paid into the system. If you work illegally -on the black - you will never qualify for free health care.
Not speaking Spanish will be a major handicap. If you weren't particularly academic when you were at school you may find it especially difficult to learn. With no Spanish and no established reputation....who would be your client base?There aren't that many British immigrants around now....so many have gone back to the UK and many more would like to but are stuck with unsaleable properties.
As for schools for your children...unless you can afford the fees for private international schools, best to forget about it, especially for the fourteen-year-old.
What would he do when he leaves school at sixteen? Half of the young people in Spain are unemployed.
To conclude, the only people who are thinking of emigrating to Spain should be retired people -and only then with good pension incomes, professional people with secure well-paid jobs lined up, people with businesses in the UK which they can run from Spain or anyone with a secure job with a contract and a good wage.
People will tell you you have nothing to lose so go for it. That is extremely foolish, irresponsible advice for people with children.
Jo's advice is sound: come for a holiday, not a package deal or a hotel stay, but renting and living if only for a month doing the usual daily chores etc. Then you can see things for yourself.
But even doing that in no way prepares you for the experience of actually living in any foreign country.