Your comments

@Chim fair enough. We all have different priorities and preferences. :-)
Social_Studies, art_therapy and foreign_languages are a suitable, quick and easy workaround for me and my notes have many tags using this underscore. Time would be better spent on other feature requests in my opinion.
Very good idea to have Notebook tabs. +1
Holding the Ctrl key whilst clicking the link I pasted into the note body opened it perfectly. Many thanks Thomas!! 

Alex please retire this suggestion as I now have my solution. It's good to get feedback on this great piece of software!
Alex, when I try to enter the link eg sulkb://kb=30_11_13,Fid=New~Records,Rid=5677 into the note body using "Insert Link" as a URL the link is underlined and blue (as a web URL would be) but clicking on it doesn't open the webpage in surfulater. However, when I put the link above in the link box I can open it perfectly.

Thanks for your feedback Thomas. :-)