Don't know if anyone is looking for Vokes filter tube? I have just purchased 12" of 38mm ID/ 43mm OD, galvanized tube from John Whitehouse of Whitehouse Flexible Tubing in the UK, for £8.96 plus postage.
This stripwound tube is made by a company called Amnitec in merthyr Tydfill and is well calling them direct, as they will often give a free short sample.