This SeaHawk has clearly been much loved and well looked after. It would appear to have only recently moved to the coast, almost certainly from Waterbeach, Cambridgeshire. The clues are the Environment Agency's style of registration number (G3605) and the "CAM SC" legend on the transom. Waterbeach is where the Cam Sailing Club has its base. The club certainly had at least two SeaHawks based there during the 1990s so this is probably one of those.
All the indications are that Buzznack II was regularly sailed single handed on those waters. Not only does this boat have a tabernacle, which is so necessary on river-based boats, but also two lines running back to the cockpit from the base of the forestay. The lighter one of these, not relevant here, terminating on the port side of the cabin door is clearly for furling the jib.
The second line, under tension in the photograph, is much heavier and attached beneath the furling gear. From there it goes straight down to pass through a substantial eye on the deck. It's purpose appears to be to allow the mast to be lowered without leaving the cockpit. The only disadvantage of a line passing over the cabin roof in this way would be that is would prevent the forehatch from opening.
Of all the SeaHawks at Brancaster, this one rests on the flatest ground. There is another picture, in the Description section of the site, that nicely demonstrates the greatest angle that a SeaHawk is likely to lean when beached.