Section 4L of the British Nationality Act introduced last year.
I've determined potential eligibility based on information submitted to Breytenbachs and Sable International. And yes, of course, it requires money to be spent on lawyers. The amount I have been quoted so far is not beyond my means and if successful would save me a LOT of money over the ancestry visa expenses. It absolutely is a gamble where I will either save a significant amount or lose my opportunity to get the ancestry visa before these insane price increases come into effect. It's not like the price increases make the ancestry visa beyond my means either, but it would sting.
I've contacted some other immigration firms to see whether I can get consensus on how much merit there is to my case and whether they reckon I should go through them for the ancestry visa (of course I wouldn't use them for that, but I figure if they think they'll make money from me either way then they'll be more honest about my prospects lol). Breytenbachs alleges that they have had multiple approvals for claims for clients born between 1982 and 1988 with a paternal grandmother born in the UK.
I'll see what comes from it. There's still some time to make a decision on whether to go with this gamble or resign myself to the ancestry visa.