B&Q, Wickes, Toolstation, and Screwfix are all excellent alternatives to Homebase. The fact that The Range may be taking over some branches is neither here nor there, as The Range is not a DIY store - it's like a glorified B&M. Which, as other have said, have already taken over a great number of Homebase stores years ago.
Way, way back in the day (almost 30 years ago) I used a Homebase store extensively, as I'd just got my first flat, and the nearest DIY store was a Homebase. They had an amazing range of goods, a brilliant loyalty scheme (called Spend & Save), they opened until 8pm (thus I could go after work), and the prices were round about right. I shopped with them for years.
And then it all seemed to change; the Spend & Save card scheme was stopped, goods seemed to be more expensive than other shops (making it worth travelling further afield), and other stores such as Wickes really began to up their game.
Coming from the other direction, we had online shopping, which of course has been a game changer. I long gave up going to any Homebase store years ago.
The one nearest to where I live now used to be a Texas - I remember being taken then once by my parents when I was little. These days, it looked like a smash & grab in a British Heart Foundation warehouse, and the shop itself was worn & tired. They had an Argos counter in it some years ago, briefly, which caused a lot of disruption when it was installed, and a lot more when it was taken out, following the acquisition of Argos by Sainsbury's, who absolutely did not wish to become the owner of Homebase for a second time.
One of the few times I went there in recent times made me want to never go again - I required a small plumbing part, which was showing as three in stock when viewed online, but couldn't be located by me on the shop floor. The assistant refused to help me look, or to get someone to help me look, because "It'll be here somewhere". So I went to the customer service desk, explained my situation (including being told no one could help me look) and said I would be happy to order & pay online right there & then and wait for the part to be brought to me, or they could get me someone who could help me find it and I would pay at the till...their choice. You don't get any of that crap at Screwfix or Toolstation, and in my city there's branches of both every few miles - usually both on the same industrial estate too. My decision as to which one I use is only ever determined by which one has the stock of what I need.
Homebase has been bought & sold several times over the last 10+ years, and my local store was already closing down to become a Sainsbury's supermarket, when the announcement was made that the entire chain had once again fallen into administration.