I may be totally wrong but I think those hoardings are referring to the whole T1 development when it says complete by Spring 2009 ie - the brand new airside shopping concourse. The new security area opens on Monday but the new extended airside area will remain the same for this summer, with a few exceptions. However by next Spring, it will have been transformed with brand new shops, cafes, bars and restaurants. I'm sure that's what the completion date is on the hoardings. I had heard somewhere that the new shops in T1 Arrivals will be open by June but that may well have changed. It's been a good few months since I've seen the plans.