I've just done this too. I started my ATPL studies, then did a few brush up lessons and re-took my PPL(A) skills test to revalidate my PPL(A) as well as get a type rating on my local club aircraft. I'll sit my exams in a few months. Getting the PPL up and running again helps you to understand all those things you're learning about when studying for the ATPL. Yes your PPL flying is done on a much smaller level than the level at which the ATPL is pitched but never the less, I found it a useful practical revision.
If you get you're flying rate right, by the time you've finished you ATPL exams, you'll have cracked the 200 hours and you can move straight into an IR.
Good luck.
