to answer your question about the slipway then I'd go for waders (if you didn't want to wear a drysuit). I'ts a downright bummer when the water comes over the top of your wellies.
I tend to wear shorts and a pair of flip flops on the Slipway but it does get cold in the winter so between December and April I try to wear my drysuit . If you are buying yourself a drysuit might I suggest you get yourself one with a ' comfort zip.......hmmm suits you sir!'
I always take dry clothes /waterproofs with me in case I get wet (shortly follwed by getting cold) If I go out and it's going to be a rough day I put me drysuit on if it's going to be a nice day then I wear less protective clothing! If you are going to buy waterproofs then make sure you buy ones that are above coastal grade.
don't go out underdressed so layer your clothing so you can whip a bit off if you start to overheat and remember to take sunscreen with you as your under attaack from three elements, reflected light, direct sunlight and windburn
I am not a great one for dressing up, but I do like to wear my "I am with this idiot T shirt ,,,,,,when in close proximity to David Manning"
does your boat come with safety euipment or do you need any advice on that
you might find something lik this useful for storing the dry stuff