There is nothing specific in the GMC guidance that covers such an event, to the best of my knowledge, however, normal guidelines apply, such as Good Medical Practice and working within one's competence, the duty to assist etc.. The fact that you are working in a non-specialist environment would make no difference in terms of accountability since the duty of care to the patient remains the same. Therefore any assistance you provide would confer the same responsibility as normal, acknowledging the practical limitations of what you can do, but if you need further clarification, I suggest you call the GMC helpline. They will talk you through the guidance over the phone. 

I'm inclined to agree with Roger Worthington re competencies and duty of care, etc. but drawing on my own experience as a doctor to a football team, I would recommend going on a first aid course run by one of the big providers, eg St Andrew's/St John's, British Red Cross, etc. I did this, and the scales fell from my eyes. 

It's important to remember that you're not there to provide GP services to those gathered there -  anything serious is going to go to the hospital anyway, so your role is going to be to add value to the eight minutes or whatever it takes between being summoned to see the patient, and the arrival of the ambulance.

Bw

Chris Ide