Richard, some texts making it clear that you should not genuflect when carrying the Book of the Gospels.
From the Ceremonial of Bishops:
“70 Neither a genuflection nor a deep bow is made by those who are carrying articles used in a celebration, for example, the cross, candlesticks, the Book of the Gospels.”
(Ceremonial of Bishops, Liturgical Press, 1989, ISBN 0-8146-1818-9, page 36.)
From the 2002 General Instruction of the Roman Missal (GIRM) approved for the USA, which can be accessed from
romanrite.com/girm.html :
“*The Introductory Rites *
172. Carrying the Book of the Gospels slightly elevated, the deacon precedes the priest as he approaches the altar or else walks at the priest’s side.
173. When he reaches the altar,
if he is carrying the Book of the Gospels, he omits the sign of reverence and goes up to the altar. It is particularly appropriate that he should place the Book of the Gospels on the altar, after which, together with the priest, he venerates the altar with a kiss. …”.
“195. Upon reaching the altar, the lector makes a profound bow with the others. If he is carrying the Book of the Gospels, he approaches the altar and places the Book of the Gospels upon it.”