Renewing an ATPL involves sending money to the CAA, you simply need a valid medical and a type/class rating that was valid within the last 5 years. I believe even an SEP will surfice for this.
A CPL is much the same, but an IR requires a renewal annually. You can let it lapse, but the ATPL theory credit is only valid for 7 years from your last renewal/revalidation.
LASORS (or your national equivilent) is the best source of clarification on such matters.