Boundary box on single text element (not text box) is bigger than the actual text

Hi there,
I've had this issue for a long time but I've just never got round to trying to fix it. Basically on a single line text element (so not a text box), the bounding box that surronds the text seems to not be in-line with the bottom of actual text. I have tried playing with the line height but as you can see that doesn't seem to make a difference.
Any help please?

