"In April 1920, Hayes sailed for London, England, accompanied by Lawrence Brown, his pianist since 1918. Hayes found a new voice teacher and managers who helped him with bookings. For the first year, he performed regularly but found little financial success. Finally, he gave a critically successful recital at Wigmore Hall and was "commanded" to perform before British royalty. This led to engagements in cities across Europe. Most received him warmly, but Hayes had difficulties when he went to Berlin, Germany. He described the performance: Well, I came out on stage, and there was a burst of hissing that lasted about ten minutes. I just stood there, and then I decided to change my program. As soon as it was quiet, I began with Schubert's "Du bist die Ruh." I could see a change come over the hostile faces, and by the end of the song I knew I had won." - See more at: http://www.afrovoices.com/rhayes.html#sthash.lBnR7Mrq.dpuf
Hayes's repertoire may have been fairly extensive though it seems that he was primarily a recitalist, as many singers were in those days if they didn't do the opera circuit. There's a 2 CD set of his recordings, released by Preiser Records, where he sings early music and baroque as well as Lieder and spirituals. The clip below (not on the Preiser set) was made in 1939/40. It's Roger Quilter's It was a Lover and his Lass, published in 1921, just months after Hayes arrived in Europe. Contemporary new music!