Sorry that I've come very late to this but I might be able to shed some light on it. My grandfather was part of the BEF and was evacuated from St Nazaire. He narrowly missed getting onboard the Lancastria and watched from the harbour as it was attacked and sunk. He was evacuated soon after and was then posted to the Isle of Man to guard prison camps housing 'aliens' (German, Austrian and Italian civilians living in the UK). It was there that he met my grandmother. After they married in 1942, he was talking to her father, my great-grandfather. They discovered that they had both seen the sinking of the Lancastria that night at St Nazaire; my grandfather from the dockside and my great-grandfather, from the the Isle of Man Steam Packet Company ship he was serving on, lying off the French port. I have struggled to find any mention of IoMSP ships involved in Operation Aerial and wondered how the story of their conversation came about. But the accounts here could explain it.