Ex not keeping to concent order

Hi there, I wonder if you can help me please. My ex husband and I went through a very long, horrible and expensive divorce. The judge signed our concent order for spousal maintenance to be 40% of his earnings for the next 5 years, moving down to 30% for 3 more years and then just down to the 20% maintenance just for the children, who are 4 and 6. He has been a high earner of over £170k a year for over 10 years. We were married for all of these. He was on on £15k when I met him.
At the end of the divorce proceedings he wiped out his business of money and gambled it all away. He is going through the bankruptcy courts as he personally owes around £750,000 including a lot to the inland revenue.

Since we divorced last September he has gone 'self employed' doing Google ad words for customers (what his business was before) and getting the money paid into his girlfriends account (as he has no bank accounts due to banks withdrawing them due to tens of thousands being owed on them through his overdrafts etc). He has admitted to me and his family that he is earning over £7000 a month but on other times he says he's not been paid by his customers and has no money. He has bullied me and black mailed me all throughout the last couple of years with money and I have never stopped him seeing the children but he threatens not to pay me if I don't let him have them for more days. He and has been paying me maintenance, in part payments, irregularly each month since September and never pays when he says he will. I have asked him to prove his earnings and show me her accounts (marking off anything not business related) and I have asked her and they both refuse.
Can I take him to court to prove his earnings and if so can the judge order to see her bank account? He didn't disclose all of his finances in the divorce as he refused all the way along. I only settled with him because it meant the house was transferred to me. I know they will refuse to provide the bank accounts because they are refusing to me. What will be the consequences to them?
I have a £22000 loan for legal fees for the divorce which I am struggling to pay with my part time job and looking after the children so cannot afford representation in court. How much will it cost me and what are my chances of sorting him out and making him pay me properly in regular payments. Incidentally he has a £30000 legal bill for the divorce and isn't paying a penny of it due to bankruptcy.
Thanks