To be more constructive than my first post here, I have to admit that it is not always so easy to get the temperature right. In winter the cold water straight out of the tap is about 13 C so I have two plastic buckets which each hold about 10-12 litres. I fill them with cold water from the tap and then sit them in the bath. I then partially fill the bath with warm water until the temperature in the water in the buckets is close to 20 C. As the room air temperature is about 20 C the bucket water will stay close to the right temperature for long enough to develop and wash the film.