In brief, after completion of 2 years of foundation training, you will apply for 2 years of core surgical training. You will need to be successful in obtaining at least 9 months of ENT in these 2 years of training. You will also need to complete MRCS (ENT).
There is a national ST3 selection process for a registrar post in ENT which spans on average 5 years.
There is an option of clinical fellowship in the UK during this training.
On attaining a certificate of completion of training, you will be able to apply for an ENT Consultant post.
Details of the process are available in the training section of the SFO website.