Hi
The leaky binnacle is as stated above almost certainly coming from the foot of the grab bars but it may be worth checking the screw holes attaching the instrument pod to the hoop and also where the hoop passes through the binnacle at the compass level. I have had leaks at both of these points.
Re the rest although it could be a waste of time but it may be worth spraying the side decks with a hose starting at the aft end and working forwards, paying particular attention to any through deck fittings such as the fairleads, portlights, genoa car tracks and the standing rigging attachment points. At the same time if you can get hold of a roll of blue paper towels put these along the lip at the outside edge of the inner roof lining in the fore cabin, salon and aft cabin and anywhere else which you might think useful. It may help to pinpoint where the water is coming in as they go dark blue when wet.
The stanchion feet on the 36C are bolted to the upright part of the toe rail so there should be very little strain and hence movement at the deck level. Having said that there is a screw in the base of the foot that goes down through the toe rail into the deck so it is worth checking those too. As the stanchions will almost certainly been well and truly stuck in the feet removing this screw presents quite a challenge.
Last autumn I had a leak coming through the access covers to the deck organisers on the coachroof. Whilst I am sure Jeremy is right re the main hatch drains, I have never been able to trace the source despite using a hose pipe and it miraculously stopped as soon as I put a dehumidifier on board.
Good luck and I hope you find out the where the water is coming in
Andrew