Would you be able to tell me what specific adhesive tape is used on the
Land Rover Discovery Genuine Factory OEM Wheel Arch Flares?

mil thickness?
mil width?
length needed to re-attach all?
Online vendor suggestions for purchase?

 

Just carefully pull yours off, once done go to your local auto parts store, they can match it up with a 3M tape, may not be the same brand but will work well.
Make sure to use a heat gun or air drier to straighten any of the moldings before reinstalling.