Just applied for warm home discount (UK only) via my UK energy supplier. This is a one off annual payment and takes form of an electricity credit by 31 March. There are eligibility rules. And only some applications are checked (about 15%). Many are not checked. Application window is only open for a short period to limit applications. When you change energy supplier a new WHD needs applying for, which means can not change energy suppliers. Am reminding you in case you have missed window in the past. Apply if unsure. Search online for online application, find correct 'phone number to apply by 'phone.
My energy supplier had to refund me in April £278 which is nearly 2x WHD. They can not budget your payments to take into account your success with WHD.