New Development HOA - Preexisting Structures

I'm hoping to get a few opinions. We have a small lake in our new development neighborhood in Florida (now about 3 years old). The HOA rules state that residents are not allowed to have a dock on the lake. However, there is one property where a dock existed many years before the purchasing of the neighborhood by a developer and before the land was parceled out for building. The board is trying to require the resident to remove the dock, but the resident argues that part of their reasoning for purchasing the property was that the structure already existed before the creation of the new development and before the creation of the HOA. Does anyone know the legality of trying to require the removal of a preexisting structure in a situation such as this? Or does anyone have any suggestions about how you would handle this situation?

Thanks in advance for any input!

Thx for the response Geno. It is a real lake, spring fed. Dock was permitted upon original establishment. But governing documents say "no docks on the lake." Owner's argument it that the establishment of HOA covenants should not be applied to something that was in place long before the HOA began.

Assuming that the current owner did not own the property when the HOA was formed, I don't see where the HOA has any obligation to give notice of a violation when a sale occurs. See 720.30851.

Under those circumstances, I think it's time to lawyer up.