Make lightweight boxes from 90 x 12mm pine and 3.6mm plywood, two 200mm square and one 300 x 200mm, then mount them on the wall to save bench space. Paint the backs to blend in with the wall colour.
Position the sides against the ends, securing with adhesive and 30 x 1.6mm nails, burying the heads with a punch. Secure the backs with adhesive and 25 x 1.6mm nails.
Sand the surfaces when the adhesive is dry, then prime and paint. Insert wall anchors and 30mm x 8g screws. Attach keyhole plates to the back of each box, then hang them.