This page offers a download to a Max OS X version of the Dvorak keyboard layout with UK punctuation.
This was inspired by the following tarind.com.
This bundle was created using the Ukelele tool.
I was using this on macOS Mojave (10.14.6), now Catalina (10.15.7).
Hopefully this makes your life a little easier by not having to create it yourself.
MD5: f1d2779e933f142c6a1b52b3504b678d (Updated 03/2020 - This keyboard now works with caps lock pressed).
Just drop the file into the
/Library/Keyboard Layouts/ directory. Then enable it through the settings.