You're best bet would seem to be a roundtrip to IST on one of the next two weekends. But it involves an overnight stay, and is pricing at £490. However, if you net the Avios earned (assuming you are BA silver) you could use 30,000 Avios to get this flight cost to £289. Poor use of miles, but on the other hand you could recruit them pretty quick as a Gold instead of Silver next year....