cheap films are normally 1 to 1.5 stops slower than it says on the box.
good films are 0.5 stops slower to accurate.
if you want your pictures on negative film (not slide film) to look better, a very easy way is to shoot everything one stop over. you will get much better tonality.
What speed is it then? At £2.50 a roll and £4 for dev and scan I dont mind fucking around with it and seeing what results I can get