There has been a fair bit of discussion in ToP of the English equivalents, particularly regarding Studland Bay. Little seems to have been aired yet about any possible Scottish "no anchoring" areas, although one conservation group did have a website listing places like Upper Loch Torridon as potential candidates.
I'm sure I've seen one suggested for somewhere up Caol Scotnish. A mussel bed, or some such?
Yes, it's on the Marine Conservation Society's site, here: http://www.yourseasyourvoice.com/mpa/?region=9
There was some discussion of it on here earlier: viewtopic.php?f=31&t=6008
Having now read a bit more about how the process works, it would appear that diving conservationists only need to take pictures of something listed as a "marine feature" for the site to be seriously considered for designation. See the MCS's comments about the Western Isles. The Scottish coastline is very long and it'll take them years to cover it all, but the "features" list is so extensive that I would expect one or more to be present almost anywhere looked at. Whether or not designation will cause us problems we've yet to find out, and RYA Scotland is involved so that's something at least.
We already have a few "no anchoring" areas, but a proliferation of them would completely alter Scottish cruising as we know it. The tone of the notice at the entrance to Loch Creran sets a worrying precedent: effectively saying all anchoring in the loch is prohibited except at the following places... I can't remember any effective consultation on this, but perhaps others have better recall.