I left law school 10 years ago at the age of 30. I had a law degree (2.1) from a top 10 university, and good employment track record (7 years in the forces). I just managed to get TC at a top regional firm (paying then about £17k) - many of my then colleagues are now in the City probably earning lots of money.
I only managed to get that TC through contacts. The HR dept had binned me, (inundated with well qualified candidates and they have to start somewhere). Do what you can. Some people worked as paralegals...but you will have to stand out. It will be difficult - but not impossible with the children.
So now, after a break for my own children, I am an in house lawyer, doing a job I do enjoy. Decent hours...and paywise I am in central London, c5yers PQE, and on just over £60k. It is not bad - but it is not about to pay for private education. DH earns a bit more than I do, and we are doing fine, but with London morgage costs, we don't have loads to spare. Both DCs will be at state schools for the foreseeable, but we may reassess in the future.
By the way, I think you have had some really good advice on this thread. Not all of it will be welcome, but don't ignore it. If you want to know additional info on salaries, contact some of the big recruitment firms in the legal sector, they will have done salary surveys - try Michael Page, Hays, Hudson etc.