Posted: 20/02/2014 at 18:47
We're in London and have clay too. Plus enormous amounts of rain (though nothing like what these poor people in flooded areas have had).
As far as I know, clay is pretty fertile, but is normally plagued from poor drainage.
My garden is teaching eons to dry...
All I plan to do is rake in some good mulch once Spring is here, turn over soil a bit once spring bulbs have done their thing and add some manure to the roses.
You should be alright just doing that, I reckon.