Thank you!!

Hi folks, I have a question regarding my Credit Agreement with Midland Mercantile Finance and wondered if anybody could offer advice. I bought a car from a used car dealer and funded it through a loan with their in-house finance company (the two companies are owned by the same guy but are completely seperate) I have noticed two things on the agreement:- The Total Amount Payable is different from the Price of the goods + charge for credit, only a few pence difference but nevertheless added up incorrectly. The lenders signature was that of the salesman from the dealership and not an employee of the finance company. Do any of these affect the enforceability of the agreement, by no means am I trying to get out of paying it but would like to keep for future ammunition if needed. Thank you very much.