If you are flying on a 744 or in September, then all LHR ones should be refitted with Suites, which would mean v:port or Odyssey. Newest econ. and PE seats are only on v:port aircraft (I think), although I found that the seats with Odyssey were slightly better (although the new headrest on the new seats is great!)If you are on an A340-600, then you will definately have v:port and the new econ seats as they come standard on these (not sure if UC should be done by then). If you are on a A343, then you will get either Odyssey which is a v.good system, or Arcadia. Whilst people are wondering that the A343s maybe refurbished, I don't think that will be by September! So, when I flew to EWR in Feb. we flew out on G-VTOP (Odyssey) and back on G-VWOW (v:port)
Enjoy your flight(s)!