I think according to my information from TF SPORT
chassis 028 belongs to TF SPORT and will be for the 2015 British GT Championship the purple and white Steel Decking liveried Vantage GT3.
It seems that MP MOTORSPORT never had the
chassis 028.
http://www.astonmartin.com/racing/teams/tf-sport
And information from 22GT RACING
chassis 029 was purchased from MP MOTORSPORT.
All this will be check in the pits for those who can.