Easiest option is to change the AutoGrow property for the Inv Ref field to True

Hi Ken Starnes  

Thanks for the reply.  Can you explain in more detail how I do this

When you click on the Inv Ref field a Properties box should be available on the right hand side of the window. You'll need to scroll up the properties to the top and you find the AutoGrow property there. If the window is not showing then you have to enable it using the View (Menu) Option then Properties

Many thanks for the help Ken Starnes - It now works!!