Yes, I think Dennis was self-counsious about singing a new song in front of a stranger, at least in the studio, so that's why for "Angel Come Home" he wouldn't let Geoffrey watch. After that song turned out so well, he was willing to accept Geoffrey's ideas for "Love Surrounds Me", which he had originally been unsure of.
Was Dennis often that self-conscious, or was it just when singing other people's songs? I mean, if he could pick up people from the street to sing on his records it couldn't have been that bad all the time, right?