Side steps

Hi guys. I recently fitted new side steps to my TD5 Disco. The front mud flaps have an adhesive foam rubber piece that goes between the exisiting plastic eyebrow and the mud flap which has not adhered correctly, even after cleaning both plastic eye brow and mud flap throughly with a alcohol wipes. The adhesive has adhered to the eyebrow ok, but not the new mud flap. This has resulted in a 2/3mm gap which is now providing an area for grit /dirt ingress. Cosmetically it dosn't look good. Question 1, How can the foam effectivly be taken off, leaving a clean surface, both on the eyebrow and on the new plastic mud flap, and 2, are the adhesive foam rubbers obtainable as a seperate item? TIA Dave