It should be easy enough to make a suitable substitute from basic components.

Kodak D-25 can be used at a temperature of 25*C and the suggested times are those given for Kodak Microdol-X when used at 20*C.

Kodak D-25.
750ml of water at around 50*C
Metol = 7.5 grams
Sodium Sulphite, anhydrous = 100 grams
Sodium metabisulphite = 15 grams
Water to make 1 litre.