If your rings were worn, the engine would smoke as well. The oil leak you have could be unrelated. Check the breather system - particularly the seperator which can block up. It is possible that there's some compression loss from the head gasket joint even though it has been replaced (maybe it wasn't done properly). To cause excessive crankcase pressure - there would be compression lost into the camshaft cavity on the drivers side of the block.
A compression test will tell if you have worn rings.
Compression on a new 200/300TDi engine is 19.5:1 +/- 0.5:1. A worn engine would be less than this, but you need to look for one cylinder reading considerably less than the other three for a head gasket leak, or very low on all 4 for worn rings.
Maximum variation is 5-bar (70psi)
Les.