Denis: Welcome to the WOA forum - great to hear from Ireland. Must be a story on how and when the W32 made it to Ireland!!
Here are some images from my boat - the rust done the hull like I see in your pic's isn't unusual... in time the SS will "rust" with a lack of oxygen and stain the hull.
Below are images linked that show what you need to look for when inspecting your chain plates..
Based on the age of all the westsails - I would recommend that you at least polish up to a shine the exposed chain plates -- and look carefully at the area around the carriage bolts... the holes are square - and the cracks from from the corners of the square hole.
If you have any doubt at all about the chain plates -- it is highly recommended that you at least remove and polish them up on both sides -- so you can inspect carefully or after 40 years it is probably time to just replace the chain plates.
Regular members have access to more information collected over the years on this and many other issues on our Westsails.
In closing - within the last few years at least 2 W32 were abandoned mid Pacific by their crews after failures to their tangs/chain plates/rigging.
HTH
Jay Bietz
Web Master