JME, have you considered making your own?
Shouldn't be that hard to make if you have access to a workshop.
First make a pattern from stiff cardboard. Measure the hole spacing, punch out the holes with a leather punch and test fit to car.
Buy some 5 mm thick x 90 mm wide mild steel strip from a place that sells steel cut to size. A 600 mm long piece should be enough to make both brackets, cut out with an angle grinder.
But care would be needed to get the bend angles right. (Large vice and heavy hammer needed)
Probably need 5 mm longer bolts to mount.