You do not need 'residential' status to live on your boat on a marina. If the owner is amenable that is enough. The council will want to inspect a leisure operators records that should show all moorers home addresses which is all the information the operator is compelled to provide to prove his leisure status.
Councils then go after anyone they happen across or on suspicion or on 'information received', who they suspect of living aboard with no main residence elsewhere. But - if the operator is in the habit of subletting a mooring on the marina (while registered user is cruising) to a visiting boat who's residential status can not be verified - and - the marina owner does this on a regular basis then only one mooring based council tax levy is charged to the marina owner.
What happens (informally) is that the cost is recouped from all liveaboards on an equal share basis sometime for as little as £50 or so depending on the numbers.
BWML like to give the impression they pay council tax for each residential boater - but they don't - they use that excuse for their high mooring fees. Some 'residential moorings' however, don't even have residents on board , but to wealthier owners they offer a greater degree security.
Getting back to evictions - that is always the right of the owners and the conditions in the agreement signed by the moorer.