what is an sar? I just got my mortgage statement and the charges were there but I was worried about rocking the boat to much

Hello everyone I am new to this sight, and have a problem, I am worried about what to do about my charges, on credit cards and bank accounts my problem is not straight forward, sometime ago I got into debt due to illness, (I am self employed) I wrote to my creditors and explained the situation and offered a reduced payment, just for a little while to help me get back on my feet. All of them declined my offer, the interest mounted, along with late charges, eventually I went to the Consumer Credit Counsel who have given me a Plan to follow and I pay them direct and they pay the creditors FREE OF CHARGE it is a charity. I would like to know whether or not I can claim these charges back only some of them have sold the debts on to other companies. I have also had Defaults registered against me. can anyone help advise me? . I have written to the Abbey about 3 account and heard back from 2 off them. 1 has agreed to pay me back £105 but I requested £125 I feel ok about that the other has paid back £32 out of £96 not quite so happy about that one but its my mortgage account and they hold my mortgage so I will put up and shut up. But am still waiting to hear from 3rd one which is £485,