I have been asked to attend a Christmas Function to take photographs of 110guests at a hotel in London, 45 miles away. They used function photography last year, were charged no fee and guests were charged £8 per print. They also want me to print off photos on the night. They want there from 6pm until at least 1am. I dont think it is worth my while as I cannot guarantee sales and my time, travel would be for free. I am thinking of asking for £250 for the evening. Any suggestions ?