A compound of formula: wherein: W is group (Wa), group (Wb) or group (Wc): wherein: R 1 is H, C 1-4 alkyl, halo, haloC 1-4 alkyl, CN, C 1-4 alkoxy, or haloC 1-4 alkoxy; R 2 is H, C 1-4 alkyl, C 3-5 spiro carbocyclyl, haloC 1-4 alkyl or halo; R 3 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 3 is absent; R 13 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 13 is absent; R 14 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 14 is absent; A is a 5 or 6 membered saturated or unsaturated heterocycle, with at least one O atom; which heterocycle is optionally fused with a cyclopropyl group, or a cyclobutyl group, or a cyclopentyl group to form a tricycle when considered together with the phenyl; R 16 is halo, C 1-4 alkyl, C 1-4 alkoxy, halo-C 1-4 alkyl, halo-C 1-4 alkoxy, or CN; R 17 is H, halo, cyano, C 1-4 alkyl or C 1-4 alkoxy; with the proviso that when R 17 is H, R 16 is not in the para position; R 4 is C 1-4 alkyl; R 5 is H or C 1-4 alkyl; or R 4 and R 5 can be fused to form C 3-4 spiro carbocyclyl; wherein R 2 and R 3 may be attached to the same or a different ring atom; R 2 may be attached to a fused ring atom; and wherein R 13 and R 14 may be attached to the same or a different ring atom; or a pharmaceutically acceptable salt and/or solvate thereof, and/or prodrug thereof, wherein the prodrug is functionalised at the secondary nitrogen of the hydantoin, as defined below: wherein L is selected from: a) -PO O - •M +, wherein M + is a pharmaceutically acceptable monovalent counterion, b) -PO(O -) 2 •2M +, c) -PO(O -) 2 •D 2+, wherein D 2+ is a pharmaceutically acceptable divalent counterion, d) -CH(R X)-PO O - •M +, wherein R X is hydrogen or C 1-3 alkyl, e) -CH(R X)-PO(O -) 2 •2M +, f) -CH(R X)-PO(O -) 2 •D 2+ g) -SO 3 - •M +, h) -CH(R X)-SO 3 - •M +, and i) -CO-CH 2 CH 2 -CO 2 •M +. R 1 is H, C 1-4 alkyl, halo, haloC 1-4 alkyl, CN, C 1-4 alkoxy, or haloC 1-4 alkoxy; R 2 is H, C 1-4 alkyl, C 3-5 spiro carbocyclyl, haloC 1-4 alkyl or halo; R 3 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 3 is absent; R 13 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 13 is absent; R 14 is H, C 1-4 alkyl, haloC 1-4 alkyl, halo; or R 14 is absent; A is a 5 or 6 membered saturated or unsaturated heterocycle, with at least one O atom; which heterocycle is optionally fused with a cyclopropyl group, or a cyclobutyl group, or a cyclopentyl group to form a tricycle when considered together with the phenyl; R 16 is halo, C 1-4 alkyl, C 1-4 alkoxy, halo-C 1-4 alkyl, halo-C 1-4 alkoxy, or CN; R 17 is H, halo, cyano, C 1-4 alkyl or C 1-4 alkoxy; with the proviso that when R 17 is H, R 16 is not in the para position; R 4 is C 1-4 alkyl; R 5 is H or C 1-4 alkyl; or R 4 and R 5 can be fused to form C 3-4 spiro carbocyclyl; wherein R 2 and R 3 may be attached to the same or a different ring atom; R 2 may be attached to a fused ring atom; and wherein R 13 and R 14 may be attached to the same or a different ring atom; a) -PO O - •M +, wherein M + is a pharmaceutically acceptable monovalent counterion, b) -PO(O -) 2 •2M +, c) -PO(O -) 2 •D 2+, wherein D 2+ is a pharmaceutically acceptable divalent counterion, d) -CH(R X)-PO O - •M +, wherein R X is hydrogen or C 1-3 alkyl, e) -CH(R X)-PO(O -) 2 •2M +, f) -CH(R X)-PO(O -) 2 •D 2+ g) -SO 3 - •M +, h) -CH(R X)-SO 3 - •M +, and i) -CO-CH 2 CH 2 -CO 2 •M +.