Ferryman Poly Tunnels We have a large range of different sizes of the polytunnels that we manufacture, We have frames covered with two types of polythene, net skirts for extra ventilation and shade net covers. A full list of replacement covers is included to fit not only the polytunnels that we manufacture but also the wider sheets for larger tunnels. polytunnel - Classic suitable for most areas in the UK and Tuftunnels suitable for the Scottish Islands, coastal, and other windy areas.