I've also read about Yoko being behind the Japan drug bust and that it was to do with the hotel Paul and Linda were staying in, cant remember where I read that but the same source then quickly went on to Pauls call to John being blocked by Yoko which makes me think it was an anti-Yoko thing.
Here's a BlogSpot that looks at when John and Paul last met (John says '76 which is why i would have thought it was then) and mentions James saying he had his photo taken with John which would put Johns date in doubt ...