This is a question which is hard to answer unless some one has done a similar thing. I dug my own lake about an acre. I have an idea of putting a boat on it and renting it out for holidays. IE just static but moving the boat once a week. Would I need planning permission or would the law be like on a canal where you can tie up for a few nights then move on.
Cannot seeing it being a problem, best way is to have a word your local planners as site access and waste disposal issues would be involved . Biggest hurdle would have been making the lake as involves lots of planning and EA permission, flooding issues etc. Also would involve rental and fire regs insurance. Wouldn't have thought it would have come under Canal Trust regs for mooring as you are not connected to any waterway.
The lake is already here I dug it many years ago plus shower and toilet. In fact the first test for my 32 after I have completed the refit is to launch it on the lake. This is where I got the idea from.