A compound of formula a tautomer thereof, or a pharmaceutically acceptable salt of said compound or tautomer, wherein: R 1, R 2 and R 7 are each independently hydrogen or C 1 -C 6 alkyl; R 3, R 4, R 5 and R 6 are each independently hydrogen, halogen, C 1 -C 6 alkyl or C 1 -C 6 alkoxy; R 9 forms a 9 to 10-membered bicyclic heterocyclyl or heteroaryl ring with R 8, wherein the ring comprises 1, 2 or 3 heteroatoms independently selected from N, O and S; wherein the ring formed between R 8 and R 9 is optionally substituted with one R 10 substituent; R 10 is selected from halogen, oxo, cyano, -OR 11a, -SR 11a, -NO 2, -NR 11a R 12a, -CONR 11a R 12a, -NR 11a COR 12a, -NR 11a CONR 12a R 13a, -COR 11a, -C OR 11a, -SO 2 R 11a, -SO 2 NR 11a R 12a, -NR 11a SO 2 R 12a, -NR 11a SO 2 NR 12a R 13a, -NR 11a C OR 12a, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 2 -C 6 alkenyl; R 11a, R 12a and R 13a are each independently hydrogen or C 1 -C 6 alkyl; wherein the ring formed between R 8 and R 9 is also optionally substituted with one or two R 14 substituents, which are each attached to the ring through Q; Q is selected from a covalent bond, oxygen, sulphur, -NR 11 -, -CONR 11 -, -NR 11 CO-, -NR 11 CONR 12 -, -CO-, -C O-, -SO-, -SOz-, -SO 2 NR 11 -, -NR 11 SO 2 -, -NR 11 SO 2 NR 12 -, -NR 11 C O-, -NR 11 C OR 13 -, C 1 -C 6 alkylene, C 1 -C 6 alkyleneoxy and C 2 -C 6 alkenylene; R 11 and R 12 are each independently hydrogen or C 1 -C 6 alkyl; R 13 is C 1 -C 6 alkylene; R 14 is a 5 to 6-membered heteroaryl or heterocyclyl ring, or a 3 to 5-membered cycloalkyl ring, or phenyl; each occurrence of R 14 and Q is the same or different; R 14 is optionally substituted with 1, 2 or 3 substituents independently selected from halogen, oxo, cyano, -OR 15, -NR 15 R 16, -CONR 15 R 16, -NR 15 COR 16, -NR 15 CONR 16 R 17, -COR 15, -C OR 15, -SO 2 R 15, -SO 2 NR 15 R 16, -NR 15 SO 2 R 16, -NR 15 SO 2 NR 16 R 17, -NR 15 C OR 16, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 3 -C 6 cycloalkyl; R 15, R 16 and R 17 are each independently hydrogen or C 1 -C 6 alkyl; and each C 1 -C 6 alkyl and C 1 -C 6 alkoxy is optionally substituted with one or more substituents, which may be the same or different, selected from halogen, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, thiol, cyano, amino, nitro and SF 5. R 1, R 2 and R 7 are each independently hydrogen or C 1 -C 6 alkyl; R 3, R 4, R 5 and R 6 are each independently hydrogen, halogen, C 1 -C 6 alkyl or C 1 -C 6 alkoxy; R 9 forms a 9 to 10-membered bicyclic heterocyclyl or heteroaryl ring with R 8, wherein the ring comprises 1, 2 or 3 heteroatoms independently selected from N, O and S; wherein the ring formed between R 8 and R 9 is optionally substituted with one R 10 substituent; R 10 is selected from halogen, oxo, cyano, -OR 11a, -SR 11a, -NO 2, -NR 11a R 12a, -CONR 11a R 12a, -NR 11a COR 12a, -NR 11a CONR 12a R 13a, -COR 11a, -C OR 11a, -SO 2 R 11a, -SO 2 NR 11a R 12a, -NR 11a SO 2 R 12a, -NR 11a SO 2 NR 12a R 13a, -NR 11a C OR 12a, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 2 -C 6 alkenyl; R 11a, R 12a and R 13a are each independently hydrogen or C 1 -C 6 alkyl; wherein the ring formed between R 8 and R 9 is also optionally substituted with one or two R 14 substituents, which are each attached to the ring through Q; Q is selected from a covalent bond, oxygen, sulphur, -NR 11 -, -CONR 11 -, -NR 11 CO-, -NR 11 CONR 12 -, -CO-, -C O-, -SO-, -SOz-, -SO 2 NR 11 -, -NR 11 SO 2 -, -NR 11 SO 2 NR 12 -, -NR 11 C O-, -NR 11 C OR 13 -, C 1 -C 6 alkylene, C 1 -C 6 alkyleneoxy and C 2 -C 6 alkenylene; R 11 and R 12 are each independently hydrogen or C 1 -C 6 alkyl; R 13 is C 1 -C 6 alkylene; R 14 is a 5 to 6-membered heteroaryl or heterocyclyl ring, or a 3 to 5-membered cycloalkyl ring, or phenyl; each occurrence of R 14 and Q is the same or different; R 14 is optionally substituted with 1, 2 or 3 substituents independently selected from halogen, oxo, cyano, -OR 15, -NR 15 R 16, -CONR 15 R 16, -NR 15 COR 16, -NR 15 CONR 16 R 17, -COR 15, -C OR 15, -SO 2 R 15, -SO 2 NR 15 R 16, -NR 15 SO 2 R 16, -NR 15 SO 2 NR 16 R 17, -NR 15 C OR 16, C 1 -C 6 alkyl, C 1 -C 6 alkoxy and C 3 -C 6 cycloalkyl; R 15, R 16 and R 17 are each independently hydrogen or C 1 -C 6 alkyl; and each C 1 -C 6 alkyl and C 1 -C 6 alkoxy is optionally substituted with one or more substituents, which may be the same or different, selected from halogen, hydroxyl, C 1 -C 6 alkyl, C 1 -C 6 alkoxy, thiol, cyano, amino, nitro and SF 5.