Actually I am wrong aceman.
The LGW 3 class 40J aircraft toilets are in exactly the same places as a 4 class B777.
2 at the front, one is behind the flight deck door and the other opposite door 1R.
The there are 3 toilets at the front of CW, one forward of 10D and 2 forward of 10G.
The 48 J version only has behind the flight deck, one forward of 10G and one forward of 10JK.