Web Part property pane text field - issue with special characters

I have a web part that allows users to configure text fields in the property pane, and this text is then displays on the web part.  This works well but for some reason when I type in certain characters that are special characters in HTML I get the corresponding coded version rather than the character itself.  For example typing in & displays & on the web part.

Is there an easy way for me to fix this so the correct characters display on-screen?

Thanks for your help.