Your school is required to hold your training records, including exam results for 5 years following completion of your course. In some cases this is in the form of a photocopy of the CAA forms. Some schools use other formats. But it should be possible for them to give you a copy of your results in one form or another provided it is less than five years since completion of your course.
The CAA will also sell you a copy if you wish. The price is something in the region of £23. If you contact them through e-mail or telephone they will tell you how to pay. They will then post the copy to you or you might be able to arrange to pick it up personally.