You can still buy the T bolts & nuts, it would be worth using the correct parts when you put it back together.
If you can't find them over there, I am sure I have seen them listed for sale by the UK specialists. Rimmers have them on their site, note that as well as the T bolt & nut, there should be a spacer, sealing washer, spring washer & plain washer! There should also be two rectangular fabric flaps under each grille which I guess are there to prevent water ingress.
Tony
<font size="1">1981 TR7 FHC Cavalry Blue
1980 TR7V8 DHC Jaguar Regency Red - sadly sold!
1977 TR8 FHC EFI Factory development car Inca Yellow</font id="size1">