You have what's left of the radiator bushings, almost everyone has replaced these by now.
The rubber aftermarket ones are probably your best bet. There will be four of these, two below the rad also, you can (possibly)l ift up the radiator and slip a new pair underneath.
The part numbers vary but for your 93 I think you should get MNA4241AB
Autozone has them on line for $1.95 apiece.https://www.autozone.com/collision-body-parts-and-hardware/radiator-mount-bushing/jaguar/xj6
all the best
94 XJ40 VDP
Oyster Metallic/Doeskin on Aero Alloys
220,000 Kilometers/136,700 MilesDaily Driver
94 XJ40 SOVEREIGN
Diamond Blue Metallic/Barley
111,000 Kilometers/69,000 MilesParts Car