Attended cremation
A full service with family and friends present, followed by the cremation. You pay the funeral director's charges plus the crematorium fee and any celebrant.
Unattended cremation
Sometimes called direct cremation. There is no service at the crematorium, and the ashes are returned to you afterwards. Many families then hold their own memorial at a time and place that suits them.
Why fees vary
Crematorium fees are set locally and can differ substantially between neighbouring areas. Early weekday slots are often cheaper than afternoons and weekends.