In England, can I buy fresh fish directly off the boat? In Trondheim, where I used to live before coming to England, sometimes I bought fish directly off the boat. The fish was fresh and cheaper than the supermarket. I am interested to know if it is possible to do the same in England. Is it common to buy fresh fish off the boat in England? 

Note: I asked the same question in Expatriates.SE, but was advised to ask here instead.
People don't become fishermen in the UK to get rich. We simply don't eat enough variety of fish for them to sell it in person. The way they make the most money is wholesaling it for export to the rest of the EU. 

That said, apart from possibly Yarmouth you are in one of the best areas in the country where you might get this service. Here's one based around Cornwall:

http://www.mouseholefish.com

They put posters up when they will be heading out. 

For more suggestions you might consider a Facebook group or similar for your town?