I'm not so sure, Aidan.
One of the clubs I belong to here in Oz recently did its own bottling. We purchased a cask directly from the distillery, had it shipped to Australia (not cheap!), paid all the import duties and taxes, bottled & labelled it (at cask strength), and then made it available to our members.
The cost per bottle worked out at AUS$85, which is about 31GBP or US$60.
Now here's the big news.....it was a 30 year old Glenfarclas!!!
How much would you pay for a 30yo cask strength Glenfarclas?
Even here in Oz, the distillery bottling of Glenfarclas 30yo (at 40 or 43% ABV) retails for over AUS$300, i.e. more than three & a half times the price we paid for our cask strength bottlings.
I think the independent bottlers are making very handsome profits.