Let me be truthful about Great War medals. I know much less about this period than others.
From the photos, those are so-called swing mounted, not the modern court mounted. The ribbons are very likely original silk, and probably not very strong a hundred years after award. The medals themselves are probably named, which helps for WW1 medal research compared to WW2 and later. If they are an unbroken set with no replacements, that is a very good indicator that an auction house or collector will offer a premium value. Some veterans have more interesting stories and careers, and their sets are more desirable. The nicks and edge knocks are probably genuine and would have happened while worn on parades or at functions. The MM is going to have a citation somewhere, and most regimental histories will have had diligent research to tie particular awards to the unit. However, the authors and publishers of that level of scholarship are long dead. If you can identify a particular title, you'll be looking on the military book secondary market. But the good thing is military book titles will be more easily found than less popular fields of history. If there are any little cardboard boxes or documentation like receipts or telegrams, they are valuable in themselves and support the entire set.
The rosettes on the ribbon bar indicate a particular threshold for that medal has been reached. The modern Gulf medal has a bar for service during a set period of hostilities. The modern Afghanistan General Campaign Star has a series of bars to acknowledge multiples of days in theatre. The CD has ten-year incremental bars after the initial twelve year qualifier for successful avoidance of punishment.
I don't recognize the bird badge, which is to say I don't know whether it is an eagle or an albatross or a pigeon. The cap badge will be easily researched to find dates, campaigns, and successions.
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Further to my last, the three lefthand medals on the top set are WW2. Therefore, the same gent served in two wars. Not as a combatant but in uniform nonetheless.
Finally, I would suggest making a display box that hangs on the wall with the details that you find. A clever woodworker will be able to make a box that has a compartment for papers and notes below or behind a glass front box.
