If I remember rightly he demanded money from Vincent and got it.

What happened then as I haven't seen this referenced for a while?

Kind of Vanished.

From what I can remember, Buster apologised to Vincent for the blackmail and it was left at that.

I remember he saw Phil beat up Vincent in the Albert but just smiled at Phil and walked way (because Vincent wanted him and Shirley to leave the house).

Also there was a Buster duff duff (which is rare) where Buster mailed something/had a folder or keys/put something in the bin? I don't really remember what he did but it was something to do with Vincent.