Since moving to the USA I've been having all of my "old" prints removed from their frames, the glass cleaned on both sides, and the prints backed with acid free paper. Likewise I've had the original mats backed with acid free paper. My framers then clean the original frame and carefully put everything back together. Because I've got a fair number of prints to be "remounted" (over one hundred) I get a "group rate", but even without that, the cost would be about the same as ordinary framing. Your Burns print has obviously become a family heirloom and is well worth conserving for future generations. You might want to consider affixing a label on the back giving the details of the family history of the print.

From what I can see of your Burns print it looks to be in good condition, and should definitely be hung in pride of place.