@CorporalCaptain - Bingo. The Reliant doesn't have it (and all her type continue not to have one even thru DS9
@Mytran - Thanks
I agree, the whole "deflector dish" is a TNG thing. You are correct that in TOS (and TOS movies) the deflectors are mentioned in plural (plus they fly around sideways and backwards at warp necessitating 360 protection.) The big dish I attributed it as part of the sensor equipment. I'm not finished with the placement of the nacelle pylons and rollbar but happy with the aft hull shape.