In the fonts folder are 100plus differing types but as you can see i only have 4 selected (attached doc)

if we delete the ones not in use will that create any problems to the system?

I don't know to say if it will create problems to the system, but the functionality of certain applications may be degenerated. For example, those fonts also serve also OO writer (or any other word processor you are using), as far as I know, so you will be left with four fonts only.

I'd leave the fonts. It's not worth deleting them, however, sometimes you can click that details button and ensure that the fonts are using 100dpi and not anything higher than this. Anything higher can sometimes make things look really weird. I had that problem a few times.

When I first installed Mandrake 10.0 back in 2004 or so, one of the first things I did was trash my system by removing some fonts.

Yeah, me too!

I was trying to improve my fonts and uninstalled 3 font libraries, libfreetype6, libcairo2, & libXft. I thought I had installed their replacements with an RPM I created, but it turns out that the fonts were installed to the wrong directory. When I rebooted I could only get the console screen. I had to reinstall the fonts I had just removed by using my Free DVD (I had no internet connection available in Mandriva at the time). The DVD was not currently set up as a repository, so I had to figure that out too.

unless you're very careful and know what you're doing, deleting fonts can turn out bad. there are a few fonts that are required just for the X server to start (usually "fixed") and if they get deleted...it's not fun trying to get it fixed.