Stimulated by Denise's article, I rang Altimed, who make the Altiform made to measure compression stockings I wear. Their representative was very helpful. I will try to report what he said, just hope I'm not misrepresenting him. If in doubt, or for more info. ring Altimed on 01509-501720.
He explained that RAL-GZ 387 is the German standard for compression stockings. Altiform are made to the UK standard, technical specification no. 40, test: BS6612. Compression stockings come in a series of classes giving an increasing degree of compression. UK class I have no equivalent in the German system (these would I think be like flight socks, and in my opinion are not a lot of use). UK class II roughly = RAL-GZ class I. UK class III roughly = RAL-GZ class II. There are RAL-GZ classes III and IV which have no equivalent in the UK. However it would be possible to get a higher level of compression in the UK by doubling up stockings. IMO anything higher than class III would only be needed in case of severe medical problems, not for sport and recovery. I am not clear whether anything higher than class II would be helpful in sport - I have only worn class II. If anyone else were to ring Altimed, perhaps they could ask this question.
Sigvaris stockings, conforming to RAL-GZ, give a high degree of compression, but are thicker and heavier than UK stockings. This IMO might be a problem in Summer. I wear my UK class II stockings even in the heat of the south of France, but I'm not sure I'd want to wear anything thicker. More important, Sigvaris stockings are not available in the UK made to measure. To me, given that everyone is different, and even our right legs usually don't measure quite the same as our left, made to measure is the gold standard.
Altiform ready made socks are available over the counter for about £20 the pair. Made to measure they cost about £45. IMO this compares very favourably with the prices for Sigvaris.
NB the Altiform representative told me that Skins socks not only don't work, they are counter-productive as they don't compress the ankle, so the blood is being encouraged in THE WRONG DIRECTION! Altimed are supplying compression stockings for recovery to several of the UK Olympic teams. What the Olympians are getting is essentially what we can buy from Altimed.
Finally, he told me something quite new to me: one of the functions of compression garments is to suppress BOUNCE by holding the muscles to the bones. 30% of our available energy in running etc is lost in bounce!!! There is also increasing blood flow through the muscle and getting rid of lactates.
For a fascinating account of an experiment to demonstrate the value of compression garments see ZOOT. PS Zoot says the benefit from sports shop compression garments is about equivalent to the benefit from ordinary running tights.