Sausage or bacon rolls = brown sauce - preferably the HP or Branston fruity variety
Fish fingers or chips = ketchup
Anything else is wrong except for English mustard on cold sausage rolls.
I beg to differ...
Sausage or bacon rolls = barbeque sauce or sweet chilli sauce
Fish fingers or chips = mayonnaise
Sausage rolls = Polish mustard or sweet chilli sauce
Ham sandwiches = Polish mustard or home made chutney
Roast beef sandwiches = creamed horseradish or stilton and home made chutney
Pork pie = home made chutney