When this went to Court (the County Court - nothing to do with magistrates) the suspended possession order would have been on terms. What were those terms and have you complied with them? Was anything said - either in the
Court order or in the lender's papers which the Court had - about charges being made each month?
Do you mean that of your extra �100 only �35 is actually reducing the arrears? If so, this seems unfair but you need to check the terms and conditions of your mortgage (you almost certainly don't have a copy but the lender should send you one as they will have the deeds and the mortgage document will be with them) to see whether this is allowed.
So far as the �15 for non payment by direct debit is concerned, I assume this is because you are not paying any of the mortgage by dd. It is quite common these days for extra costs to be imposed in this situation, but it depends on what the mortgage document contains. Is there no way you could set up a dd?
You could use the lender's formal complaints procedure and then go to the Financial Ombudsman if necessary, but its best to get all the facts together first.