Upvote:1
It starts from the intended date of travel. The UK Gov website gives this example βYou can apply from 16 March if you plan to travel on 16 Juneβ. https://www.gov.uk/standard-visitor-visa You book the appointment as part of submitting the online application, and you can change your booked appointment anytime up to 3 weeks before your travel date (the latest acceptable date for the appointment is stated in the email confirmation received after completing the online application). For example, for an intended travel date of 7 June, you could complete the online application on 8 March and have your appointment up to 17 May.