Another UK`er here from yorkshire top end
i started a grow last year and ended up planting 1 outside in the middle of the year when the light times wer over 13hours daylight
she was in a 1 gallon garden pot i did it just as a tester as my mates said it would die but it loved the outside light and fresh air
check out this thread of mine which has pictures of my plant outside
https://www.rollitup.org/indoor-growing/84914-white-widow-grow-2.html#post1015727
this year i will be planting about 10 plants in couples of 2 in 5 different areas of the countryside away from any roads paths houses so they wont be killed and spotted, i will be posting pictures of them later in the year
my advice if u are going to grow outside never tell anyone where they are and watch your back when visiting your plants always take a different route as u might get followed.
Happy budding
as undo said slug pellets a must i didnt use slug pellets but did use egg shells broken up into small pieces .. but you will need to use something as mine did get attcked at one point and its amazing how much they can consume in one day...