Coukld I please have some advice in what to cosider when writing a risk assessement for work activites outside of normal production, whilst on reduced working to keep a team of 3 busy. We have established ther will be no fist aid on site for some of the days, the team will only be working 4 days out of five, is this allowed and this goes for suprevison as well. The team will move to small tasks, sush as making bird boxes to donate to charity to fill in the time, for approx 4 week. Is there anything else I need to consider?

I wouldn't be happy myself just saying "there is no first aid", especially if you are doing real work with actual tools. 

At a minimum there should be a first aid kit, a means of communications, and an appointed person.  I note that https://www.hse.gov.uk/simple-health-safety/firstaid/first-aid-appoint-someone.htm says "An appointed person must always be available whenever people are at work."  The appointed person needs a briefing, but doesn't necesarily need an external training course and a first aid qualification.