It's not a dedicated launching site, but I've used
www.geograph.co.uk
to get pics of proposed destinations & launch sites. Inevitablty someone will have taken a pic of a pier or slip where you are planning on lanching / going to. If you move to a nearby mountain top (This tip is probably not a lot of use on the east cosat, but works well on the West od Scotland) you occasionally get an "aerial view" taken from the top of a mountain by a hillwalker.