A compound of Formula (I) and pharmaceutically and/or veterinarily acceptable derivatives thereof, wherein: R.sup.1 is H, C.sub.1-6alkyl, --C(A)D, C.sub.3-8cycloalkyl, aryl, het, aryl-C.sub.1-4alkyl or het-C.sub.1-4alkyl, wherein the cycloalkyl, aryl or het groups are optionally substituted by at least one substituent independently selected from C.sub.1-8allkyl, C.sub.1-8alkoxy, OH, halo, CF.sub.3, OCHF.sub.2, OCF3, SCF.sub.3, hydroxy-C.sub.1-6alkyl, C.sub.1-4alkoxy-C.sub.1-6alkyl and C.sub.1-4alkyl-S--C.sub.1-4alkyl; A is S or O; D is H, C.sub.1-6alkyl, aryl, het, aryl-C.sub.1-4alkyl or het-C.sub.1-4alkyl; R.sup.2 represents aryl.sup.1 or het.sup.1, each of which is substituted by at least one substituent independently selected from B, provided that when R.sup.2 is substituted by halo then it is also substituted with at least one other substituent independently selected from B other than halo; B represents aryl.sup.2, het.sup.2, Oaryl.sup.2, Ohet.sup.2, Sarl.sup.2, Shet.sup.2, SC.sub.1-6alkyl, halogen, CHF.sub.2, OCHF.sub.2, CF.sub.2CF.sub.3, CH.sub.2CF.sub.3, CF2CH.sub.3, aryl.sup.2-C.sub.1-4alkyl, C.sub.3-6cycloalkyl, C.sub.3-6cycloalkyl-C.sub.1-4alkyl, C.sub.3-6cycloalkylC.sub.1-4alkoxy, C.sub.3-6cycloalkyl-O--C.sub.1-4 alkyl, C.sub.3-6cycloalkyl-C.sub.1-4alkoxy-C.sub.1-4alkyl, OC.sub.3-6cycloalkyl, SC.sub.3-6cycloalkyl; wherein the aryl.sup.2 and het.sup.2 groups are optionally substituted by at least one group selected from C.sub.1-6alkyl, C.sub.3-6cycloalkyl, C.sub.1-6alkoxy, OC.sub.3-6cycloalkyl, halo, CN, OH, CF.sub.3, CHF.sub.2, OCF.sub.3, OCHF.sub.2, hydroxyC.sub.1$alkyl, C.sub.1-4alkoxy-C.sub.1-4alkyl, SC.sub.1-6alkyl and SCF.sub.3; n is 1 or 2, provided that when n is 1, m is 0 or 1 and when n is 2, m is 0, wherein if m is 0, then * represents a chiral centre; R.sup.3 is H, C.sub.1-6alkyl, C.sub.3-8cycloalkyl, C.sub.3-8cycloalkylC.sub.1-6alkyl, aryl.sup.3, het.sup.3, aryl.sup.3-C.sub.1-4alkyl or het.sup.3-C.sub.1-4alkyl, wherein the C.sub.3-8cycloalkyl, aryl.sup.3 or het.sup.3 groups are optionally substituted by at least one substituent independently selected from C.sub.1-6alkyl, C.sub.1-6alkoxy, CN, OH, halo, CF.sub.3, OCF.sub.3, SCF.sub.3, hydroxy-C.sub.1-6alkyl, C.sub.1-4alkoxy-C.sub.1-6alkyl and C.sub.1-4alkyl-S--C.sub.1-4alkyl; at each occurrence aryl, aryl.sup.1, aryl.sup.2 and aryl.sup.3 independently represent phenyl, naphthyl, anthracyl or phenanthryl; het.sup.1 represents an aromatic 5- or 6-membered heterocycle which contains at least one N, O or S heteroatom, optionally fused to an aryl group; at each occurrence het, het.sup.2, and het.sup.3 independently represents an aromatic or non-aromatic 4-, 5- or 6-membered heterocycle which contains at least one N, O or S heteroatom, optionally fused to a 5- or 6-membered carbocyclic group or a second 4-, 5- or 6membered heterocycle which contains at least one N, O or S heteroatom. ##STR00001##