@Silver: thanks for enquiring, I appreciate that 
Yes, I resolved it in that I deleted the caches in the ObsidianCache folder, and the workspace file in the .obsidian folder.
I am not sure what did the trick, but I have a feeling it may have been deletion of workspace.
Yesterday when I tried out the Ubuntu theme I had no problem, switched back to my normal theme, then back to the Ubuntu theme and the page was blank. Deleting cache did not do the trick, deleting workspace did.