I’ve Got Some Patio Fruit Trees In Small 8cm Pots. When Can They Go Outside In Bigger 50cm Pots

Question

Live in West Midlands, they’re currently just a single stem/trunk

Answer 1

This, really, depends on the exact trees in question. Generally, though, you can assume that it is safe right before the leaves sprout out for the year, or just as they are starting to show budding.

These collections of articles will offer more information on zone 8, which would be your area's equivalency to ours:

https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-8

https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-8/zone-8-fruit-trees.htm