Shed base

hi.
I'm looking into building a shed in the corner of my garden which is actually fenced on three sides making it a great place to stick a shed. The ground at the moment seems to be muddy clay which doesn't have a problem with flooding or anything. My question is - can I get away with digging down maybe 50mm and using plenty of breeze blocks as support for my shed base instead of slabbing the whole area? I would then lay a membrane down, blocks on top and then a 50mm shingle topping all around the blocks. I appreciate that the block are thicker than the 50mm but a step up wouldn't be a problem. I've seen people use deck blocks but I'm concerned that my blocks may sink Hope this makes sense and that someone can advise.
Thanks