Shetland: Shetland Disability website
This site is not strictly a places to visit website, however we came across it in our research.
It does not provide concession prices but does provide good information on accessibilty to various buildings in Shetland.
It was worth adding to our list.
https://www.shetlandaccessguide.org.uk/AccessGuide.aspx
This information is correct as at April 2013