I have struggled and struggled with this one. Eventually I am left with:
46A Agreement holds involving four of the Roman seminaries Y _ _ _ I _ A _
54A Turned gas on with ... this S_R_W
55A Copy in one hand is a follow-up to CD
I_I_A_E it must be imitate, I cannot see the wordplay though.
47D Approaches stage with drink (5,2) _ _ E _ _, _ P
Please help and am I the only one too thick to see these anmswers???