Peter, you did not need to 'revalidate' your JAA PPL, but you did need to get it re-issued every 5 years. This was a purely administrative process and required only that you held a valid medical and had held a type or class rating valid within the preceding 5 years. No specific test or experience requirements existed for the re-issue of the licence, particularly not the PPL Skill Test or any part of it.
A successful IR proficiency check currently may count as the 'training flight with an instructor' required to revalidate a SEP Class Rating by experience. However, under the new rules (i.e. from 1 July), only a class or type rating proficiency check or skill test will count for this purpose.
I'm not sure where MJ is coming from with the statement that there will be "no more renewals - just revalidations". The same distinction between revalidation before expiry and renewal after expiry remains in respect of all ratings and certificates under the EASA implementing rules.