In the piezoelectric ceramic material PbZrxTi1-xO3 (PZT) there is controversy about the structure of PZT at the Zr-rich end. This region has always been considered to be of rhombohedral symmetry, but lately there have been suggestions that in fact it is monoclinic. Recent experiments using a conventional x-ray diffractometer in Oxford seem to suggest that the true symmetry may depend on the method of manufacture of the ceramics, the difference being between mixed oxide sintering and sol-gel techniques. To resolve this problem it is necessary to use very high resolution powder diffraction spanning a large Q-range, since the difference in powder diffraction patterns between the two is very subtle. The key objective of this work is to establish whether the structure does change with preparation, and if so how this affects our understanding of the origin of piezoelectricity in PZT.