If an item was lost on a Grand Central service and recovered by the on board crew, it will be handed into the terminating station which will be Bradford Interchange, Sunderland or London Kings Cross.
In order to see if the item has been located at either Bradford Interchange or Sunderland, please contact the Northern Rail who run those stations on 0800 200 6060.
If the terminating Station is London Kings Cross, the item will be handed to the Excess Baggage Company, contactable on 0330 024 0215 and available Monday-Saturday 7am-11pm and on Sunday 8am-11pm.
Alternately you can complete their online report form here - www.lostproperty.org.