With my cynical hat on, these manufacturer unofficial “scrappage” schemes will just be out of usual discounts. All the mainstream car brands have been offering heavy discounts (usually via finance incentives – “deposit contribution” and the like) for years which has almost nullified the steep rise in list prices.
I used to buy cars at 6-12 months old which would be a good saving on the most heavily discounted new price. These days dealers seem to be sitting on used stock with higher prices than they can do new – presumably they do sell to people either in a hurry, or who still think like I used to.
A quick look on drivethedeal – even the most basic Focus you can get £5200 off list (rising for more expensive ones) and still have 0% PCP or HP finance. And you can get another £1500 “scrappage” too if you have something old to get rid of.