The guide for using petrol in boats published by The Boat Safety Scheme can be found here
Depending on your engine (inboard/outboard) various pages can be opened relating to your set up.
Read it carefully and follow the advice !
Q. I have read it is now acceptable to have glass bowls on fuel / water separator filters (and pumps ?) But the drain screw must be metal with a fibre washer. Can anyone confirm this ?