Gary,
At a 5% flat rate a loan of £10'250 would be:-
60 x £213
48 x £256
36 x £327
normally with a documentation fee of about a hundred quid on top of the first payment. His £260 might be him being crap with a calculator but is possible to spread the documentation fee across the term (makes the first payment easier but you have to pay interest of a doc fee then...) which would fit with 48 months.
If it is 60 months then it is likely that he has tried to stitch you into a payment protection scheme - which are generally not worth a toss (apart from £50 in the salesman's ass pocket....).
JJ
You gotta tie yourself to the mast my friend, and the storm will end.