It certainly appears unused.....If you give us a close-up jpeg of the bottom where the floorplate drops in, we can confirm just which Ross it would be from...
If you found it in the UKicon, there's a possibility that it could be a spare for the MkIIIB order. Cleaned up and top-wood found, a decent Ross may just rise from the ashes....Were you in the US, I could supply you with all the steel bits it needs- with the way the sand shifts these days, unfortunately I'm not prepared to send anything that's not paper offshore (or up to Kanada)