Excellent idea, MissF. If it were me and I knew of a company who could revive and restore the chair as successfully as *aggie"s, then I'd let them restore the leather chair in its current state. But it's possible specialist companies like that are few and far between these days.
Given that the chair is over 70 years old, unless it hasn't had a great deal of wear, it probably indicates that it was well-made. Furniture these days is often glued and stapled and clearly not going to last for years as in the past. I'd definitely want to keep the chair for sentimental reasons and maybe think of it being passed down through my family at some stage. If money isn't a problem, I'd have it restored and reupholstered in leather, or for a more modern twist and perhaps to reduce the cost of the work, I'd choose some very nice fabric instead of leather.
And in either case, maybe a toning throw on it if it's going into the conservatory ? As glammananna points out, lots of sunshine maybe would fade the chair whatever is used to restore it!