When ever i try to launch the game it takes straight to the fallout 4 Xbox one marketplace page even though I've already bought and installed it through the disc, the game itself still seems to be installed on my system.

Any help with this issue is appreciated, thanks.

Try power cycle of the unit Hold and press the power button for about 10 seconds until it is off.

Possibly the xbox is not reading the disk in the disk drive so check the disks for any scratches and reinserting it.

Try other game disks that you might have or other disks and see if they can be read.