For Fixed wing the ATPL/CPL contains PPL privileges. The SEP and MEP revalidations are the same for ATPL/CPL as for PPL.
I would assume the type rating would apply to PPL as well as ATPL/CPL.
Also I don't think you can hold a PPL and ATPL at the same time so you might have to surrender your ATPL to get a PPL which you might not want to do.