It takes a tremendous amount of time and careful research to put together this kind of an archive, and it's invaluable to anyone doing research about the Proms, repertory, and the artists who appeared on the programs. I can now find out with a few keystrokes which works Eva Turner sang in what years, rather than painstakingly spending hours going through programs. (The search returned 71 items from 1934 through 1948, not long before she retired. Perhaps the most surprising items were her appearance as a Rheinmaiden for the Goetterdaemmerung Act III scene with Siegfried and singing Verdi's greatest soprano aria, "Tu che le vanita" from Don Carlo, the latter in her very last Proms appearance. If she ever appeared on the operatic stage in either of these roles, I'd like to hear about it.)
My one suggestion would be making it possible to view all details of a season, not just a list of the concerts.