The main checks that we have found necessary are listed below;
Screws fastening the heavy duty aluminium bridge onto which the mast is stepped - check tightness.
Concealed screw locking in the top section of the Spinlock cleat. (ours came adrift at the worst possible moment with a partially hoisted gennaker!)
Screws fastening the mast step plate.
Screws fastening the transom rudder fixings
Screws fastening the thwart seat - a loose seat is perhaps a lesser concern than a ripped wet or dry suit - tighten them!!
Screws fastening the grip strip to the gunwhale
The furling mechanism needs an annual clean and lubrication. The large machine screws holding the furling unit can and do work loose. Check the tightness of these screws annually - if one was lost during sailing it could result in substantial damage to the rig.
The mast top sheave needs cleaning and lubricating.
Do check the main halyard for signs of fraying. Any sign of wear cut it short, heat seal the end and replace the bobble. The original main halyard (Kevlar) is not tolerant of fraying and will snap without warning if these signs are ignored.
Check the Tack line for fraying. If wear is evident the line will need replacing as the line length is relatively critical to the operation of the Gennaker and cannot be cut short.
 
The list of checks is not long, and many take seconds to do - attending to these annually makes for a very trouble free dinghy.