Dont be so sure its dodgy you want to be very sure before you accuse people of such things.. i agree that he should have fixed the items you asked.. that is if he agreed to fix them.?.
but you need to be so careful id just give the seller a call and say nicely "hey just noticed the brakes still felt odd and the oil leak was still there and we agreed to fix them" wait n see what he says.
if however you agreed that they would be fixed only if they were rwc items then you must trust they pass, because rwc's are such vague things, how someone interpretates the wording is correct, even if two people interpretate it different.
so you really need to discuss with all partys your concerns.
a good example is.. interiors i mean the rule is the discretion of the inspector so if he feels its not safe thats it, based on nothing but opinion..
my two cents