I will try and clarify a few points.
The Springbank Society started off as costing £15 per year to membership fee. This was to cover the admin, as we run the Society ourself and do not use a marketing company. After the first couple of bottlings, the society was neglected, the website had been taken over by porn-bots and many folk had joined the forum who were not actually society members. It was in a pretty poor state.
Christmas 2007 we invested in a new website/forum/on-line shop. We also employed Janet to run the society, and at the same time we emailed everyone who had paid £15 and informed than that if they replied to the e-mail, we would offer then the lifetime membership for free until March 2008. After this date anyone joining/re-joining would have to pay the £50.
The society membership entitles you to 10% off all standard products (Springbank 10, 100 proof, 15, Longrow CV, 10, 100 proof, 14, Hazelburn 8 and Campbeltown Loch) from the Cadenheads Shops or the website shop. You also get a nice membership card, a t-shirt and access to the society bottles, which we always try and price reasonably (£25 for a cask strength 8 year old...not bad).
It also gives you access to pre-orders of any new products, which is where I come to Leither.
As I have said before, LFW, Royal Mile and TWE are all great supporters of ours, however they are not our only customers and we try not to undercut any of our customers. As an example Berry Brothers & Rudd and Cadenheads London have it at £74. The Cadenhead's Shops are not owned by us, they are franchise and they set their own prices based on their overheads.
We also receive support from wholesalers throughout the country who have to make a margin before they sell it to retailers.
Its not easy
This problem only occurred because we tried to make a small amount available to Whisky Live visitors and society members. If we had released it all to retailers first we would have been equally criticised by many society members for not allowing them to get it first, particularly if they were not able to get it from LFW, RMW.
There is now no Springbank 18 year old left at the distillery. We never had enough to justify putting it on our online shop, therefore it was only released to pre-orders.
Again, I hope this answers your questions.