The growth I referred to was explicitly Argos, which has seen consistent growth through all of 2020, with Nov/Dec being 8% up year over year.
8% isn't huge, but it contributed to the majority of Sainsbury's overall growth in the period, and it's a massive turnaround for Argos given it's revenues have basically stayed about the same level for a decade.
Online sales as a percentage of all retail sales in the UK have been steadily increasing by about 2pp per year for the last decade until 2019 [0]
In 2020 this increased from 19% to 28%, from £76b to £99b [1]
For Argos sales to only be up 8% in 2020, or £320m, isn't good, it took just 1.3% of the extra online sales. Remember also that Argos (on the whole) remained open for collection during the lockdowns inside of Sainsburys.
8% isn't huge, but it contributed to the majority of Sainsbury's overall growth in the period, and it's a massive turnaround for Argos given it's revenues have basically stayed about the same level for a decade.