As much as it was someone else's business the British where rather miffed by the unrestricted Italian submarine warfare which started 12th August 1937. Only patrols by the British and French Fleets with orders to sink any subs encountered deterred the Italians from continuing. A possible POD could be an over enthusiastic Italian sub commander putting a couple of torpedoes into a British warship. This would probably lead to a full naval blockade, limiting foreign intervention by Germany and Italy and armaments from Russia.
Another possibility might be war between Italy and Britain in 1937
Perhaps a good thing for the world as Germany was in no way ready for a war, and after some early reverses British industrial and financial superiority would lead to eventual British victory (with shiny new toys and experience in using them). Benny would probably not survive in power and any illusions of Italian military superiority would have vanished. This would mean that if Germany did continue it's land grabs and Europe was still plunged into war in 1939, the Italians would be very unlikely to intervene. Hence no North African and Mediterranean adventures, vastly improving the allies position
and possibly shortening the war.