Harry,
Do you just need the hook? Apparently, it's the same part as the hook that goes on top of the spare (650017) which TRF has for $4.91 now.
The part numbers for the whole lower bracket are the following:
601994 Pad, mounting, spare wheel pan (3)
611875 Plate, reinforcing, spare wheel (1)
650017 Bolt, hook lower (1)
YN2908 Nut, nyloc (1)
WP0008 Washer, plate (1)
WQ0308 Washer, lock (1)
HN2008 Nut (1)
TRF has the whole upper kit or parts here:
TR4-TR6 spare tire clamping kit
Marv probably has spares though.
Scott