My question is ... I have photos in lightroom but I would like to start again from the beginning and learn to organise properly, can I just uninstall Lightroom and start again from scratch, am i likely to come up against any issues.
No need to uninstall or reinstall. In Lightroom go to File->New Catalog. Choose a descriptive name that you will recognize. The new catalog will be created, and will have no images in it. If you reinstall Lightroom it will just open the same catalog you have been using, and it would be necessary for you to create the new catalog anyway.
Thank you Jim...