The seaside without the surf sums up one difference between McLaren Vale and Margaret River.
McLaren Vale is tucked up in the Gulf St Vincent with Kangaroo Island and the Eyre Peninsula taking the brunt of the fierce weather from the Great Southern Ocean. This is fortunate as this makes the vintages more even. This part protection also allows vineyards to creep closer to the ocean edge since the salt spray blown inland is reduced.
Margaret River has far greater exposure to the two oceans, the Indian and the Great Southern and the most westerly vineyards begin further inland along Cave Road.
A similarity they both have is the ripening season which is controlled by the inland heat flowing south though note that while McLaren Vale has a latitude south of Margaret River the style of wine is more akin to the Barossa Valley than Margaret River.
The first release of the Trennert Shiraz was the 2007 followed by the 2008 and 2009.
This 2020 was the last of the three dry vintages beginning with the 2018. Compare this Trennert to a Barossa and Eden Valley red and enjoy the difference and again I note McLaren Vale is not Margaret River.