Thanks for that, it works, or at least it solves that problem. It creates another slight problem which is that the video now starts by flashing up the poster frame which I have set to the last frame of the video. i.e. I used to have

- start of flyin video
- flyin
- stop on destination
- restart flyin video
- flyin
- black screen

now I have

- flash up destination
- start of flyin video
- flyin
- stop on destination
- restart flyin video
- flash up destination
- flyin
- stop on destination

Still not ideal but it's one step forward.