A quick web search showed me that several firms (Carob Growers, Trevor White Roses, etc.) carries Poulsen Renaissance Roses in the U.K.
Poulsen grows an immense number of different roses in a large number of different rose collections. Renaissance is just one of these. It is not always clear what the distinction is between the different collections or which collections are available in which markets. However, do visit their website to see their remarkable selection.
I only grow a couple Poulsen Roses, because people gave them to me as gift plants. They were likely just purchased in supermarkets, but the plants are remarkably vigorous and disease-free. The two varieties I grow are Rosa x 'Poulty019' (sold as Gigi) in the Party Collection and Rosa x 'Poulpar065' (Sold as Apollo 2008) in the Parade Collection. Both are planted in-ground in mostly sun and have reached heights of over two feet.