This is on Northern Polytunnels website -
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Planning Guidelines for PolytunnelsPolytunnels generally do not require planning permission so long as they meet the following criteria:
The polytunnel should not be taller than 3 metres.
You should only use the polytunnel for domestic use
The polytunnel should not be nearer to the road than it is to the nearest part of your house
The site you wish to place your polytunnel should not have a listed building, or be an area of Natural Outstanding Beauty.
The polytunnel should take up less than 50% of the garden surrounding the house. In Scotland this figure is 30%.
The above list should give you a good idea of where to place your polytunnel to avoid having to seek planning permission. However, it’s always a good idea to phone your local planning office if you’re at all unsure.
Please note, these regulations don’t cover commercial polytunnels, or polytunnels that will be used for commercial purposes. If you’re planning on installing a commercial polytunnel it’s important that you look into how planning regulations may affect your proposals."
This is the link to their commercial polytunnels -
https://www.northernpolytunnels.co.uk/commercial-range.html