It's a 125 year lease, which could still be several million pounds for a piece of land this size in a residential area. But if the council don't want houses built on it, and place restrictive covenants on the land to prevent that and require it to remain a greenfield site, then the price of that lease would plummet. If the Football Club took some responsibility to provide and maintain a community area as part of the agreement (e.g. a community football pitch or dog-walkers area), then it's possible it could drop to zero.
I personally wouldn't expect two pitches, a car park, and a club house to cost more than £1m, even with legal and planning costs.
In
this video Spencer says that the funds are have been allocated for phase 1 and have been voted on by the Board. Presumably that's the Football Club board, for which we don't see minutes.