I think this is a mature male Steatoda bipunctata our naitive false widow. The spider in the picture has a certain 'cobbiness' about it and the legs look a little too stripey to be S. grossa or S. noblis. I must say though that the abdominal markings do look a little noblis like.
Best wishes, Lewis.
Steatoda nobilis. Looks like an immature adult, the legs are stripey when spiderlings & seem to darken up with age, how big was it?
They usually shy away from contact with humans and are quite skittish. Wandering males (more gangly, smaller abdomens but with a similar "shield" like marking) I'd catch & relocate, but females are docile & tend to stick to their webs/bolt hole, if they are undisturbed & have ready food supply. I wouldn't be too keen on having them in the bedroom/shower, but happy enough if in other rooms. I usually have a resident female around the place somewhere, one living in my front room window frame right now. I have lots of other spiders around that are more likely to bite...I rather like S. nobilis & feel quite privileged having them around.
Hi Lewis, here's a photo of a S. nobilis spiderling (3-4mm?) I had living in the front room, their legs can still show the stripes up to ~7-8mm body length as far as I have seen...