Abstract: Compounds of formula (I), or a pharmaceutically acceptable salt thereof: ##STR1## wherein L is NH or O;X is N or CR.sub.3 wherein R.sub.3 is hydrogen or C.sub.1-6 alkoxy;Y is N or CR.sub.4 wherein R.sub.4 is hydrogen, halogen, CF.sub.3, C.sub.1-6 alkyl, C.sub.1-6 alkoxy, C.sub.1-6 alkylthio, C.sub.1-6 alkylsulphonyl, C.sub.1-6 alkylsulphinyl, C.sub.1-7 acyl, cyano, C.sub.1-6 alkoxycarbonyl, C.sub.1-7 acylamino, hydroxy, nitro or amino, aminocarbonyl, or aminosulphonyl, optionally N-substituted by one or two groups selected from C.sub.1-6 alkyl, C.sub.3-8 cycloalkyl, and C.sub.3-8 cycloalkyl C.sub.1-4 alkyl or disubstituted by C.sub.4 or C.sub.5 polymethylene; phenyl or phenyl C.sub.1-4 alkyl group optionally substituted in the phenyl ring by one or two of halogen, C.sub.1-6 alkoxy or C.sub.1-6 alkyl groups;R.sub.1 and R.sub.2 are independently selected from hydrogen, or halogen;Z is a group of formula (a), (b) or (c): ##STR2## wherein n is 2 or 3; p is 1 or 2; q is 1 to 3; r is 1 to 3; andR.sub.5 or R.sub.