Charlie - these are exactly the sort of questions I was hoping for - thanks. They're helping me to see that it's unrealistic to do it on my own, in an untested boat, without a buddy boat, without any prior experience of the crossing. You and Mike have provided the sound voices of experience that I was asking for. They have helped to clarify my options for getting the boat back (assuming I purchase it). Many thanks.
It's the trailer + ferry option for me. 😊