For a long time (since 2011) the file I linked to here was one I scanned myself. However, the link now points to the official DSA form. All pages of the DL25 are included in the file, and this one also includes the eco-driving bit (which should satisfy some of the anal retentives out there)! Click the image to download a copy.
A blank DL25 consists of a front marking sheet (DL25A) and two carbonless copy pages (DL25B and DL25C) underneath. There is an explanatory sheet (DL25D) at the back.
The examiner gives the candidate the back two sheets (DL25C and DL25D) at the end of their test, whether they pass or fail. They also get a Pass Certificate if they pass the test.
DL25B has a back side, which the examiner completes back at the test centre.
DL25C (the candidate copy) also has a back side, detailing the appeals and complaints procedure. DL25D is also double-sided.
The PDF file contains DL25A, the back side of DL25C, both sides of DL25D, and the back side of DL25B in that order.