You do NOT have to resit your test after being banned for drink driving, unless the court orders it.
This would normally be in a case where the driver is quite old and had an accident, or sometimes a very new driver.
In the first 2 years after passing your test you get 6 points or more then you have to resit your test, but drink driving carries NO points, just a straight ban so this does not apply either.
The only exception to this is if you are banned for drink driving in Northern Ireland, where everyone has to resit their test.
56 days before your ban ends, DVLA will write to you with an application form to start the process of getting your licence back. They write to the address which is on your licence so if you have moved it will not arrive. You can get a Form D1 from the Post Office to make an application as well.