What is his rash?

[Lushmetender]

Is this likely to be impetigo? Been treating it as ringworm which daughter has but this is not responding- if so what are the rules on school attendance?

I can't see a picture, but guidelines are here: www.gov.uk/government/publications/health-protection-in-schools-and-other-childcare-facilities/chapter-9-managing-specific-infectious-diseases

Impetigo does indicate exclusion until it's crusted over or 48hrs after antibiotics are started. No exclusion needed for ringworm. If you can't get a gp appt, maybe try a pharmacist who could help identify it & tell you if you then need to see the gp.