Chris, yet again a lot of articles have disappeared, this formula has been posted in the relevant section twice before, once I think by Tom Hoskinson who used to use the developer himself.

The "Ilford Formulae & Packed Chemicals", published 1960 and the two Ilford Manuals of Photography that I have with it in all show the formula correctly as does LFA Mason (of Ilford) in his book Photographic Processing Chemistry.