I was reading an article about them today being "thrifty" by re-using clothes. Thrifty it may be, but I think re-using baby clothes is more of an emotional thing . . . you remember your older DC wearing something and can't wait to put the new one in it too.
Do you really think those were actually Harry's shoes? I know they are exactly like them, but who keeps shoes for 32 years???? Wouldn't it be more likely that it's some old fashioned firm who is still making the exact same style?
I suppose they could have been stored in a wing of some palace somewhere and dug up for re-use. It's considered unwise to re-use shoes, but I suspect these weren't worn very much by poor little Harry and I can imagine Charlotte coming across them in a pile of stuff and declaring "Mummy! MUMMEEE!! I want these shoes!"