@ Musiclover Yes I am using Bandstand with Win 10 64bit with BIAB 64 and jBridge.
It seems that the Halion 3SE free version comes with no sound sets. You are expected to already have a version of Cubase installed which allows Halion to use the GM set that is included in Cubase.
Thank you yet again, your reply motivated me to have another go again, to install Bandstand which now works fine in windows 10. I like the sounds in it too.
And thanks to Matt for starting this thread.