The bottom bracket that supports the radiator is too flimsy and too exposed, for a "gentle" bump against a high kerb bent the frame up and back, fortunately not damaging the radiator. Is there a support bracket available to reinforce this bracket and tie it to the main crossmember just behind it? Or, other than being more careful, is there another solution?

Are you missing the front sound panel?

If you mean the white slatted piece across the front, no. If it's the black plastic pieces that fit underneath the white piece, well, they're in the workshop, somewhat redesigned! But since they're only plastic, how do they help our problem?