"I guess the high ticket prices are needed to pay for all the uniformed security guards now policing the festival."

There was one pub last year with the type of security you mention, and my understanding is that they were paid for by the pub's management. I also understand that this was to do with more general security legislation as interpreted by the venue in question, and not to do with the festival's requirements.

"the concert side of things seems a real mess with no-one in overall control, no clear ticketting system"

The concerts are programmed and the ticketing system is in place. The first mailout has just gone out and details are on the Sidmouth website.

"It's no longer a big festival"
Maybe not compared to Glastonbury, or even Cambridge, but in a folk context there are still few that can compare. The profile of artists, length of the festival, and range and number of events still make Sidmouth one of the biggest folk festivals in the country.