The spider in your photo looks to be an immature Steatoda nobilis (noble false widow) as the legs look somewhat stripey (they become more uniform in colour as they mature).
They do like man made structures & are mostly found on/close to everyday things around us - window frames, porches, conservatories, cars, exterior walls, etc. It would be good if you could get some shots of the other smaller spiders, S. nobilis can live in close quarters to a totally harmless & much more numerous species: the missing sector orb weaver (Zygiella species), they are often mistaken for each other.
It's hard to say whether the smaller spiders (if S. nobilis) are the offspring of this individual, but without a better photo, it doesn't seem the most likel scenario? Spiderlings tend to disperse when small.
They're not aggressive & bites are commonly accidents in which the spider is inadvertantly squashed against the skin, now you know they are there it's worth giving the frame a once over every now & then (including the undersides).