Your SkyDiveCentreRepository
inherits from GenericRepository<DiveCentre>
and doesn't implement the ISkyDiveCentreRepository
interface.
Simply explicitly implement it:
public class SkyDiveCentreRepository :
GenericRepository<DiveCentre>, ISkyDiveCentreRepository
// ^^^^^^^^^^^^^^^^^^^^^^^^ this
Without it.. you can't do simple things like this:
ISkyDiveCentreRepository repo = new SkyDiveCentreRepository();
If you can't do it.. Ninject can't either.