I got five years UK visit visa issued in 15/10/2018 as my plan was to travel in December 2018. Now i postponed my travel to April or maybe will travel in June 2019. I would like to ask is it possible for me to use the visa or i will neet to get a new one. i.e because i did not use the visa for more than 3 months from the issue date does this mean the visa expires? Also is there any specifc period on which i have to use the visa to avoid invalidity?