[dazultra2000]

Sounds more like a Steatoda Grossa than a Nobilis, but still a "false widow", yes. But it could just as easily have been any one of a number of many spiders.

False widows are not uncommon in these regions. I live in Poole (I went to BU as well) so am only a couple of miles away, and last Summer I had hundreds of the buggers around. I fully expect them to make a comeback this year too, and with a new puppy in the house I'm even more worried.

Best you can do is what you already did. Trap it in a glass (being careful of it's legs) and let it go outside somewhere.