Gavin
No a lazy bed as such but I did this last year to a patch of grass. I too am on heavy clay.
Mowed it of tight to ground level a couple of times.
Covered the whole are with plantex.
Cut crosses on the planted where I was to grow anything, bug out a bucket of soil/turf, back filled with manure and compost.
In this "no dig" bed I grew very good crops of courgettes, pumpkin and out door toms.
This was a picture taken on the first day, plantex peg down and ready to go:
I cant seem to find a picture of it planted up but in this picture you can see ther same bed this year, the one in the middle at the back of the picture. This spring I removed the plantex and dug over the bed and created a raised bed. All the couch under the plantex was dead and the soil dug very well. I did skim the top 2 inches of to remove most of the dead turf. This is stacked in a corner and will go back onto the bed in the autumn.
Hope that helps.
Jerry