Hi bluebell… just my thoughts… am not sure if it´s worth growing strawberries in a polytunnel… perhaps it would be optimal to grow heat loving plants e.g. toms, cucs, melons. And perhaps other annuals. Strawbs are “perennials” and can be a nightmare when their runners start wreaking havoc. We have like 7 beds (5m x 1.5m) of strawbs growing outside. In addition, strawbs need the cold to produce fruit. We have several varieties of strawbs in order to “stretch” the harvesting period. My recommendations would be korona (early), Florence (late, plus my fav!), amandine (everbearing)… I have also planted some new varieties and trying them out… Donna, daroyale and deluxe.
Our polytunnel has 2 beds… 1 bed designated for toms and the other cucs and melons. And salads thereafter….
Just my two cents worth. 🙂