My references show 9310 is an inactive reference, so I'm not surprised. For the UK, the equivalent steel you need will depend on the application:
Case hardening: BS EN 10084 14NiCrMo13-4 (1.6657)
Open die forgings: BS EN 10250-3 33NiCrMoV14-5 (1.6956)
Case hardening bearing steel: BS EN ISO 683-17 16NiCrMo16-5 (B32)
You will find other international equivalent specs for this alloy in the Worldwide Guide to Equivalent Steels and Irons.