That looks like another steatoda nobilis false widow - feeding on a house spider? Tegeneria sp.
What do you think Peter?
Steatoda are very capable predators and I've heard that they can take tegeneria (a common prey item for daddy long legs spider - pholcus phalangoides). Woodlice seems to be the more usual steatoda diet in areas where I've observed a web for any length of time, with the odd beetle (including rove beetles large enough to be considered a serious threat to the spider).
Regards, Matt Prince