There are only Two people with licences to collect bluebell seeds in the country. ( licences given by defra ) So I don't know how others can sell bluebells unless its ok to dig up bulbs, If you know, please do tell??

One licence is a farm in kent, who sell wild bluebell seeds from their website: www.farnellfarm.co.uk

Its a great site where you can see where the bluebells have come from. You can buy as many packets as you require (foil packed!) and also buy other farm produce, such as cobnuts.