March 16 (Reuters) - Serco Group Plc SRP.L
* Named preferred bidder to operate new grafton correctional centre (ngcc) in New South Wales, Australia
* Contract for operation is expected to commence in 2020
* Estimated total contract value to serco over a 20-year term is approximately AUD2.6bn Source text for Eikon: ID:nRSP6442Za Further company coverage: SRP.L