This is what the RCAHMS/Canmore says about Copyright:
"Canmore is protected by copyright. Information and images from Canmore can be copied or downloaded for private, non-commercial research without charge. Multiple copies can be freely made for use in the classroom or for other formal educational purposes. All output from Canmore must include the following acknowledgement: © RCAHMS. For commercial or other usage, see the Copyright page: (http://www.rcahms.gov.uk/copyright.html)."
Obviously, the keyword is 'private research'. For that reason alone it could be understand that you don't pass this information to the rest of the world by placing a direct link to the files or photos parted from the 'Terms of Use' and acknowledged by registration.
There is of course also a financial aspect on the use of Canmore information as can be seen on the Copyright page (link above).
Cheers,
Jan