Regarding sales of tickets on ebay , there is a requirement that all auctions indicate the face value of the ticket
Business sellers offering tickets for sale to consumers on eBay must comply with the Price Indications (The Resale of Tickets) Regulations 1994 (guidance is available at
http://www.dti.gov.uk/ccp/topics1/guide/pricetickets.pdf). The main requirement is that the face value of a resold ticket has to be made clear to the consumer at the point of sale.
eBay requires that all sellers -- individuals and businesses -- include this information in their eBay listing description when offering tickets for resale on eBay.co.uk
So presumably any auction not showing this information can be taken down if ebay are informed. So if the touts haven't complied then shop them!
However ,It shouldn't be forgotten that tickets can be picked up at bargain prices close to the date if pickup can be arranged (typically for beausejour), so could be useful for anyone making late arrangements.