Vitvia co-operated in providing Saturn 9900 ridge bars for my Halls Supreme 812 greenhouse. Halls sold me two greenhouses yet could not provide any spares. Only after I searched the market and found Vitavia, did I realise the similarity of the ridge bars and took a risk in ordering two. Slightly different shade of green, otherwise identical. A good result for me. Shame on Halls for inadequately looking after their customers. Great credit to Vitavia for supporting non-customers. Thanks to Robbie.