I think Filon was born in 1995 at Warsaw Zoo. An account of a breeding attempt between him and Raika at London was given in 2001 describing Filon as a 'six-year old male who had fathered cubs at Dudley Zoo with Raikas older sister'.
Either this attempt resulted in nothing, or Raika miscarried (which I believe has happened on at least one occassion), or she gave birth and the cubs died.
Hari, the only tiger cub successfully raised by ZSL London in recent decades, had some of his toes bitten off by his mother and had to be hand-reared. He was born about 1996 I think and was sired by a male called Martin (possibly on loan from Thrigby), and I've no idea who the mother was. I don't know Raika's age but she is younger than her sister Sarah at Dudley and Sarah is 14. So she would have had to have barely been a year old to be the mother of Hari, which is improbable.
Am I right in thinking that Hari is now living in Austraila? I know a male of the same name sired a litter at Perth Zoo in 2008. He was on loan from a collection in Cairns. Sarah and Rakia must be litter mates as Rakia was born in 1995 at Tierpark Berlin according to the infomation sign at London Zoo which would make her 14 as well. Thanks for your help