Neither the SelectHeight.bas nor HoleRecog.bas create buttons for you. It is the responsibility of the add-in author to create these buttons, but it is not mandatory. For the SelectHeight add-in, the add-in author declined to create a toolbar button for whatever reason. So in order to use SelectHeight.bas, you need to create a button yourself. Here's how:
First, make sure that SelectHeight.bas is loaded by using the Add-ins dialog.
Press OK on the Add-ins dialog to close it.
Make a new toolbar using the Toolbars tab of the Customize Toolbars dialog box.
Make a new toolbar button using the Commands tab of the Customize Toolbars dialog box.