Update, this keg is now empty.
Thanks to a couple of Xmas parties I was able to finish this keg of beer really quick. The sourness really never took over, I think I could taste something off but not 100%.
Thanks all
kegged the beer, add the potassium metabisulfite to most of the beer but kept about 1 gallon in a small glass carboy with airlock to sit and age just to see what happens!
Thanks again
Thanks for those quick replies. I'll add that potassium metasulfite to the keg. I have 10 g so I'll be taking off 1 g and I'll hide it in a corner and try it in a few months to see how it tastes.