Hi,
That's a copy and past of an email I received from UK CAA on May 2015
Your ATPL examinations are valid for 36 months from the date of your final examination. If you have not managed to gain a Part-FCL licence issued by the EASA State that issued your Medical within those 36 months, that is both the CPL(A) and the IR, the examinations expire, within Commission Regulation (EU) 1178/2011 as amended, Annex I (Part-FCL), Appendix there are stated credits should you only gain the CPL.
I hope that the above information is of assistance.