Who knows, I do think he has room in his budget for £100million or so. Whether the issuing authority would honour them the land, with a much reduced value than it would be in real terms as something else (after Peel have ploughed over £250million into the site already), remains to be seen.
I think the feasibility study will be the decider, for £3.1 million (or £6.2million depending on where you read) you would expect a pretty comprehensive business case. It will need to be water tight to even be entertained is my understanding, otherwise it will be dismissed out of hand before its chance is heard in a tribunal.
If he has £100m floating around I can envisage better use for it than resurecting a financially failed airport!