Hi I am currently trying to completly remove sql server 2012 from my machine, when I click uninstall from the control panel then > remove, I have no option to select and instance to remove and i've no idea why.
When you deinstall SQL Server you have to select the correct program in the "Progams & features" windows. (appwiz.cpl)
Hint: It should be the program with no size.
Start the program and you should be guided through the de-installation routine.
If you don't see any option to de-install an instance, then you might not be running the correct program version, or you might not be on the server you are trying to de-install the SQL Server instance from.