wherein X is either (a) a phenyl group optionally substituted by 1 or 2 substituents each independently selected from halo, CR3, C1-C4 alkyl, C1-C4 alkoxy and hydroxy, or (b) a thienyl group; and Y is an imidazolyl, pyrazolyl, triazolyl or tetrazolyl group optionally substituted by 1 ...