Browett only joined Dixons in 2007. The economy went pear-shaped shortly afterwards and Browett's strategy involved "raising Dixons' game" to the extent that TWO rivals effectively gave up.
Browett's strategy is clearly explained in the article: he stopped the sales commissions to reduce the pushiness. He trained some 14000 staff to reduce their ignorance. He got out of foreign territories—a good move given the state of the economy in many of them, especially Italy—and began a programme of store refits.
Note that the latter process takes ages to complete; you can't just shut down every store in the land for a couple of weeks to do it. The manpower simply isn't there, so it's inevitably going to be a rolling programme of surveying each site, drawing up plans for the new layout, ordering the furnishings, signage, etc., then hiring shop-ftitters to fit it all over a period of a couple of weeks. (Less if you're lucky.)
To put this in context: the Italian equivalent to Texaco, previously known as "AGIP", rebranded itself as ENI a few years ago. Despite this, and despite the new brand still using the old "Roman wolf" logo, there are still some old "AGIP"-branded petrol stations in Lazio's countryside, where I live. One only got the refit treatment a couple of months ago. The other is still there, on the Via Cassia.