Ashall was born in Addis Ababa in 1954 and received his medical education at St Mary's Hospital, whence he qualified in 1978. Dr Geoffrey Irvine, the medical superintendent at Chogoria Hospital in Kenya, where Ashall spent three months in 1973, inspired Ashall to turn to surgery after qualification; he decided to specialise in plastic surgery after a rotation appointment at Wexham Park Hospital, Slough. He moved to Northern Ireland for his senior registrar training, becoming consultant plastic surgeon to the Belfast Hospitals in 1992. In 1991, flying to take up a training fellowship in Florida, he learnt on arrival that his wife, Lucina, had been killed in a road traffic accident. While at Belfast he developed an interest in post-mastectomy reconstruction. He leaves two sons and a fiancée, Molly, to whom he had become engaged shortly before his death.