The
CDT test will benefit you if you've been diagnosed with an alcohol problem in the last 3 years, but if you haven't been then the DVLA won't be looking for any sort of period of sobriety from you. I would recommend seeing your GP every 2 months from now and logging with him/her that you aren't drinking and things are going well for you. It's better to have a long GP record that you've stopped drinking than a few private CDT tests. You have to pay for a CDT test but your GP should provide you with a liver function test via bloods for free every few months to keep a record of the results for that. Your ban will fly in, in the first month or two of mine it really dragged but now my bans up and I'm waiting for my medical and it flew (in NI you can't have the medical until your ban is already over.) It sounds like you're wanting to do all the right things to get your licence back, best of luck!