No, they’re not captive, just awkward to get at. You’ll need either a box spanner or a socket with a universal joint adapter to get at them (8 0r 10mm, can’t remember which!). Once you’ve got them loosened a bit then mine came completely free by finger pressure. The tricky bit is avoiding dropping the nut and associated penny washer down behind the wood trim at the back of the locker…..

    Have fun

    Ian C