It's not like they have completely scrapped them and come up with new tests.
Unless I'm wrong and I'm happy to be corrected.
The rules changed a few years back. TOCs were allowed to set their own test in addition to the mandatory OPC ones. Mechanical comprehension was removed and new tests were added.
Myself, a Trainee, and a Driver who I sat my assessment day with, were all in the cab the other week discussing our assessments. So much has changed at my TOC and the tests I sat, other than Group Bourdon, basic English (Glop test), and the MMI, have changed, been scrapped, or new ones added.
The VSE (visual search exercise) is relatively new and gaining more ground and now, due to Apprenticeships, GCSE English and Maths are pretty much going to become a requirement.
From the standards. The tests, pass rates, and requirements are reviewed on a 5yr basis and if the tests are changed significantly, everyone's lives are reset. A review is due at any point now so we may see another change in the tests.