This law firm is not registered in the UK and is certainly not registered with the OISC.
It is impossible to get a visa to work as a domestic worker of any sort in the UK unless you have worked for the same employer for at least a year in his household outside the UK, and you must be able to provide evidence to prove this.
To get any sort of work visa for the UK you would need at least a degree level education. You would never use anyone in the UK to process your visa. There are no agencies, law forms or anyone else who can secure a visa for you.
The only way you can get any sort of visa for the UK is if you apply yourself at your nearest British Embassy, High Commission or Consulate. You submit your original documentation and pay them direct.
Visas are never issued in the UK unless you are already living here. Money is never paid to the UK and never by Western Union. You pay in your local currency direct to the Embassy. You cannot get a visa with scanned documents.
Have nothing else to do with this person.
And please use your common sense. What sort of parent would employ a complete stranger from half way across the world, whom they have never met, interviewed, had police checked or taken up references for, to look after their children?
ALL unsolicited job offers are scams. ALL - EVERY SINGLE ONE.
EDIT There is also no such thing as a caution fee. Complete rubbbish!
Honestly, I can understand your frustration, but if the school stated it is going to focus on "current students", that leads me to believe that your husband was not a 'current student' when these changes took place, and if that is truly the case, you may not have any recourse because schools are not obligated to stay open for every student that ever registered for classes there :-(.
I suggest you do a couple things first before calling an attorney who will charge you $$$$ to represent you, and will represent you only if he/she feels that you can only win (if they do it on a contingency fee basis) - or they'll tell you they'll try, and start charging you right away.
Politely demand that you be allowed to leave a message for, or speak with the Dean of Admissions / Director of Admissions etc. . . depending on the term used for a person in power.
Read through your husband's paperwork (admission paperwork, and anything else you have, for the wording that states - in some way or another "Admission to going out of business college does not guarantee a diploma." If you can find that on anything, or even on their website anywhere, sorry dear, you folks are out of luck, and would be best off at this point to save yourself the hassles of a long drawn out court battle (if it would even get to that point), spending extra $$ that your husband wouldn't be earning on an attorney, for no guaranteed recourse, and check with another college or university regarding their transfer credit policy, and get your husband going in the right direction so he can finish his degree ASAP.
The more you delay, and the more institutions you end up going to, the more time / $$ it will cost your family due to lost credits, etc.
Forget about this institution - why would you / your husband want his degree to come from an institution that for some reason, is having difficulty maintaining business, and may end up going out with a scandal?
Sorry, this may not be what you wanted to hear, but they are the cold hard facts.