Put it on top of the clover. You'll be OK as long as it's not on a hill where it can wash it off in a thunderstorm. Hayfields, yards, etc. it is a common practice to lime on top. I would probably go ahead with 2 tons/acre in case of a little loss.
I understand the clover in the spring and summer but sometimes you just have to look at the long term. While there is nothing wrong with putting it on top, I prefer mine on disked soil and then disked in lightly. Just me.
Now, your seed mix: For soil building is a pretty good mix. By letting it grow, did you know that (or what I've been told anyway) that the roots of the rape and turnips will help loosen soil compaction. Probably won't help with the hard pan though, it should be a little deeper. Clover helps with the N.
