I finally gave in and got myself two packets of Mr Fothergills 'Marvellous Mushroom' spawn.
The instructions say the Oyster mushroom should be grown on Wheat straw. Its not easy to get round here (Barley straw is the most common) and I wondered if anyone has grown these and used Barley straw instead of Wheat?
i have seen it grown on toilet paper.
http://www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/PDF/oyster.pdf (http://www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/PDF/oyster.pdf)
here is a link on how to do it.
Barley straw is fine as is paper, card, natural fabrics, woodchips/logs (from deciduous trees, hardwood gives higher yields), corn cobs & stalks, feathers, coffee grounds etc...
Pesonally I wouldn't of bought common oyster spawn as it is usually cheaper to buy a pack of oyster mushroooms from a supermarket & use then to innocculate the substrate.
http://www.allotments4all.co.uk/smf/index.php/topic,26874.msg264017.html#msg264017