Maybe one of these similar products would be of interest:-
BAYSTONE Shower Tray Panel Riser Kit Square/Rectangle Trays 1200mm Plinth Adjustable Feet
Easy Plumb Panel Riser Kit for Rectangle Shower Trays Upto 1200mm Plinth Feet Legs
BAYSTONE Shower Tray Panel Riser Kit Square/Rectangle Trays 1200mm Plinth Adjustable Feet
Easy Plumb Panel Riser Kit for Rectangle Shower Trays Upto 1200mm Plinth Feet Legs