Early Ilfospeed was fully developer incorporated, something Ilford kept very quiet about at the time because they wanted to sell Ilfospeed processors. I used an Ilfoprint machine with Ilfospeed and made my own Activator from Sodium Htdroxide with some Sodium Sulphite and Potassium Bromide added to keep the base fog free and extend the life of the actrivator. I use Hypam 1+4 instead of stabiliser and then the prints went into a second fixer bath before washing. I must have processed many thousands of Ilfospeed prints through my Ilfoprint machine.
When Ilfospeed was updated it was no longer developer incorporated although there was still a weak image like those in your tests Roy.