I found the answer on the CIC web;- z, E+ R" t* m4 b: F" V& \( r+ b. R# [
"The certificate must have been issued no more than three months before you submit your application" , V3 _: c* _ m) R8 X 9 b( |; e% M; f, z7 s) ROurs were more than one year when we applied.