OK, so ultimately I'm being lazy and asking my tech to do something for me. It's a very basic premis but if the single select equals something in one field, I want another field to show a reference code.
i.e. if [project type] equals "web update", I want [project code] to show "WEBU".
I have been going round in circles and am now digitally dizzy, so if one of you wonderfully knowledgeable users can point me in the right direction, or tell me it's not possible, I'll go on my way. But I hate being beaten by an app - granted it's a fantastic and possibly business-saving app but nevertheless...
UPDATE
I was thinking far too small... by creating an app with the different project types, I can now link to the app in whichever field I want, AND see how many of each are being used in the Epics/Stories in my Agile-ish project board.
I really love SmartSuite.