My daughter is letting a room to students,how should she declare income to inland revenue?

my daughter is letting a room in her 2 bedroom flat to foreign students who are learning English, she will need to declare her income to the inland revenue, this is her only income. If she keeps receipts can she claim the cost of buying food for these students against her tax, she will be feeding them breakfast, evening meal, and providing them with a packed lunch for school, also she has to pay for a taxi to collect these students from their place of arrival can she claim for this.