The prototypical shed situated farthest away from the baseboard edge is unusual in that it has a ridge vent and additional vents on each sloping roof. For a possible solution, and a way of developing structures from the toy end of the market, have a look at this mock-up. it shows how cladded sheet material, applied to the basic Hornby Loco/goods shed building, might improve its prototype appearance and save you buying new structures. To develop the mock-up, i’d suggest the following: Model Scenery Supplies’ plastic tin sheet for roofing; either Dapol/airfix ridge roof vent clad with the same material or a homemade vent, clad in the same way; a homemade wide-spaced rib joint to represent asbestos sheeting for upper gable ends; and cardbacked brick sheet, to cover over unwanted apertures. obviously, you’ll need to hack the structures about a bit to create openings on the long wall side, for locomotive entry, and to adjust the width, according to your requirements.