Block paving issue

[dave7108]

In my wisdom I thought I'd paint our block paving grey using a paving paint. But it doesn't seem to have adhered where there is still traces of a clear sealant I put on around 3 years ago. Is there a solution here without stripping everything off? Some sort of primer then recoat it all again in grey??

[tozerman]

Would it be possible to simply turn them upside down? Assuming they are std paving blocks....