Unless we get Kompany back for the 2nd half if the season, the current centre half pairing won't win us the title, never mind get us as far as possible in the CL.
Any centre half purchase in January won't be cheap, if we can get somebody decent, but we will make that money back by winning the title and getting through to the last 8 or last 4 of the CL, and having 2 good runs in the domestic cups.
God forbid if Otamendi got injured over the coming weeks. A pairing of Demichelis and Mangala would be a disaster waiting to happen.
City should spend again and go for another centre half. Hopefully they will get it right this time. I appreciate there's no guarantee's.