Hi Leeus1,
Unfortunately all of the LGW 777s have not been refurbished with Thales/new WT+/WT. You will get the 'standard' BA product that is available on all of the 747s, 767s and a large proportion of the 777 fleet (all of the RR fleet and some of the GE fleet).
Some of the ex-LHR aircraft moved down to LGW a few months ago in order to offer First class on selected routes (namely the Caribbean). Some of the native LGW 3-class 777s were then moved to LHR and refurbished with Thales, new seats and also converted to 4-class config.
Hope that's of help.