These guys, if you have them, will likely be found in the corners of your doors and windows. We’ve had this species resident on our French doors for several years running now and this association with this ‘habitat!’ is noted in (*1).
We absolutely love the pattern and dark colour of this species. These guys are small and you may think they are a spiderling of some other species.
They are another species of Orb Web Spider (Family Araneidae) and their compact web is spun in the corners of windows and in our garden fairly often on fences.
(*1) Bee, L & Oxford G & Smith H. (2020) Britain’s Spiders: A field Guide. Second edition. Oxfordshire: Princeton University Press