It’s possible that Trident-UK may have the right ones. The web page doesn’t seem to have photos of these sorts of items, but they are listed at:-
http://www.trident-uk.com/shop/acatalog/Wayfarer_Hatches_Fastenings_Fixings.html
The most likely candidates are towards the bottom of the page, but you may need to ring to check they’re what you need.