Weird how the advice given is so different! We will go on the advice of the consultant and not inform them unless we are told to. If the DVLA have a problem with that they can take it up with the consultant giving the advice! My laymans understanding is that you only have to inform the DVLA about something if it affects your driving, it doesn't affect his driving so therefore we won't tell them at present!
At the end of the day it won't be your consultant who gets the fine or gets his license revoked or invalidates the insurance due to having a sleep disorder.
If you check DVLA website medical conditions -sleep disorders -osa is listed there .
Its up to yourself but be careful because if should anything occur when driving they will slam the book at you.
If you are on therapy its just filling in the form stating cpap and compliant and you get the standard ok letter back to drive ... honestly can't see what the problem is with doing that,and your covered.
I have been a driver myself for over 25 years never had any accidents or fallen asleep at the wheel was worried myself about informing them and left it 6 months but it was'nt really worth the worry the ok letter came back in 8 days and im now nearly 6 years into therapy and have'nt heard from the DVLA since then.