No High Sierra option at clover boot screen

[JohnL2016]

remove sierra disk, only have your high sierra disk in pc

then follow instructions above on installing clover etc

Your suggestion did work. I was able to get to the clover boot screen and select the HS disk. It hung half way through booting, graphics drivers I imagine, so wasn't able to boot into HS. Changing the boot drive did mess up the audio when I booted in the Sierra disk but I was able to get it back by removing the HS disk. Think I'm going to give it a rest for a bit and try again when things are a bit slower. Thanks very much for all your help.