Hi Josh, sorry for the delay, I suspect that's down to time difference!
I've found the problem. I'm new to WordPress, this is my first attempt at a site (although I've built other sites in straight HTML and WYSiWYG software). The HELP referred to metaboxes which is a new term to me and I didn't understand what that was or where it was. I just happened to notice that the slide show was listed in a box in the right hand bottom corner of the slide properties page with a tick box. Ah, Eureka, this must be the meta box so I ticked it and all works fine now. I apologise for this but at 69 theis old brain doesn't work as fast as it used to :-)
I posted the answer to my other question about sizing slides on the relevant post.
Many thanks for your response.