As long as your weather is staying between 65°F and 85°F, it will be fine outside although I've heard it's been rainy in England lately, moreso than usual, do you'd have to watch out for that. If you have a real 600w LED, then your indoor results will be just as good or better. When an LED says "600w" it usually just means as an equivalent, which is bologna. Their actual draw is probably 75-125w so in that case, outside is almost guaranteed to be better.