Yes, this is a noble false widow, Steatoda nobilis.
They do like porches, window frames/sills & conservatories. If it is outside & out of your way I wouldn't really worry about it, females tend to be rather territorial once they have set up home (usually close to a bolt hole). They're not dangerous and are really quite skittish, not aggressive. Bites usually occur when they are crushed against the skin.
They are able to survive the winter weather, so is unlikely to wander indoors if it already has made a web. Certainly relocate it to somewhere with less human traffic if it concerns you (I removed one from my bedroom last night, don't mind them in the living room, they seem to largely stay put), but if they are in your area, they have probably been there a while and you may find it is replaced by another individual in time.
There is good info on the species on the NHM website.