You can either get a free 30 minute slot with a few solicitors, or go back to CAB. If the person is rushing, ask to make an appointment where you can discuss things when they will be able to "focus on your questions" which is code for "stop fucking about".
If they get tersey with you, ask to speak to their manager, and wait. Explain to the manager that you have come in, in a vulnerable position, looking for practical advice, and have not appreciated being spoken to in a rude, condescending and completely flippant way. If they are no better, don't get drawn into a fight, but ask for the address of where you can send a formal complaint to their superiors.
Then double check the address online when you get home.
You are only 32. You have plenty of time to re build your life. Having the children away from you may seem like having your heart ripped out, but it is perfectly healthy to spend time away from your children, so you can work towards giving them a good life. A good life means a mother who has confidence, and can demonstrate to them that it's okay to depend on yourself and not stay in intolerable situations.
It's no surprise you have ended up in a marriage like this if your mother was in the same position. Children tend to replicate the marriages of their parents. Do you want YOUR children to end up in a marriage like this?
If you mother complains again, you can tersely remind her of all the complaining she does about how she sacrificed her life. She has taught you by example not to do the same.