Flying time does not expire, however you may have to 'refresh' on flying training to date, however you should still be able to pass after 45hrs if you are a 'good un'.
Exams do expire, you have 12 months to pass Skill Test after passing them, if air law has expired you will also have to re-take prior to going solo again.
If exams were taken some time ago, syllabus could have also changed from CAA to JAA.