Ah that perhaps does change things a bit, perhaps there may be a key legal difference there re: the prospects of his current case?
Maybe something along the lines of if he had willingly disposed of it (perhaps even if done so absentmindedly) then he doesn't have a claim as I'd guess there are T&Cs relating to the rubbish tip that anything you willingly hand over there becomes the property of the council or at least that you forfeit any right to recover etc.
But presumably, if his claim is that some third party binned it instead (apparently his ex) then he's not a party to any agreement forfeiting the property or relinquishing any claim to it, instead, the drive still belongs to him and is on their land.
If a kid accidentally kicks a ball (or I guess these days loses control of a drone) over your garden you're obliged to hand it back, so I guess his argument is that this is valuable property that he's not willingly relinquished and just wants back, the council then has an argument re: cost/health and safety and he's got some counter-argument re: some plan he's come up with along with specialists and investors.
I guess if someone accidentally dropped say an engagement ring in a skip at the local tip the staff would perhaps assist in recovery, it's not something you willingly intended to relinquish to them... but that's a lower barrier for assistance, I guess he's got to argue about how reasonable his request is given the councils concerns but if his story has changed then that in itself might scupper things.