The distinction between "petrol" and "diesel" oils is a bit of a myth with modern day oil blends. A typical supermarket oil will say suitable for petrol and diesel, but here we're talking the everyday low stressed engines not highly tuned stuff that perhaps requires a more exotic lubricant (supposedly).
When I was involved with Vauxhall OHC engines in the 1980's, camshaft wear was almost a pandemic as neglected engines knocked out their cams....we have all bought used vehicles with oil like black tar or dismantled rocker boxes full of tenacious sludge, all a consequence of lack of oil changes. This made me look more closely at oils and found that in the small print the API...American Petroleum Institute classified oils as either S, for service in petrol/gasoline passenger vehicles, or C (commercial?) indicating diesel engines. So a basic spec for an oil will say API SL/CF, the suffix letters used indicating a higher spec as to the blend and the tests the oil will meet. These have changed as the world of oil progresses to meet changes in engine design, materials. So suitable for both petrol and diesel motors.
Then we get manufacturer's own specs in an effort to corner their own niche market, and there are also military specs as well! Not to be outdone the European manufacturers have their own specs, ACEA standard followed by the classification with a typical format A3/B3. In all cases for API notation the higher up the alphabet you go, the better the oil blend.
Lots out there on the web, there is more to oil than you think but at the end of the day it's just good filtration and frequent oil changes that you need to do. The men in white coats have done the donkey work.
I lubed my petrol ASTRA on supermarket "diesel " oil for years, it was cheaper than the "petrol " oil, and the small print API spec was identical on both types......These days I still change oil and filter at half the maker's service interval and the top of the engine (twin cam VV type) looks brand new. Not like the old days of a black hole under the filler cap.
Swarfy.