There are loads of threads on here about the cost of living and energy bills. I had free cavity wall insulation a few years ago and I'm really feeling the difference, and most importantly my energy bills have not skyrocketed recently as I am managing to reduce my heating requirements. (I own my current home but have also had it done in my previous home that was rented). But I haven't seen any posts about the free insulation.
I've had a quick Google and the scheme still seems to be available to home owners and renters, and according to the government website is available to many folk who might not think they're eligible (see screenshot below). Looks like energy providers HAVE to offer the service too.
Won't post a link because I know I wouldn't click on it but it's on the first search pages.
Might save a few quid.