Can this £30 bottle of Steel Seal save my cheap V8 Jaguar?

After more troubleshooting and trips to the garage with my troublesome Jaguar S Type, there's reason to believe that my car might be suffering from a failed

how hard is it to replace head gaskets on SV8? - Jaguar Forums

Can this £30 bottle of Steel Seal save my cheap V8 Jaguar?

Steel Seal Blown Head Gasket Fix Repair Sealer - 8

Steel Seal Blown Head Gasket Fix Repair Sealer - 6

Steel Seal Blown Head Gasket Fix Repair Sealer - 6

Steel Seal Blown Head Gasket Fix Repair Sealer - 6

Head Gasket Sealer for 8 Cylinder Engines - Steel Seal

Steel Seal Blown Head Gasket Fix Repair Sealer - 8

Jaguar X308 XJ8 Rust Removal, Painting and Underbody Weather

Special Tools???? - Jaguar Forums - Jaguar Enthusiasts Forum

Can My Cheap V8 Jaguar S-Type Be Saved From The Scrapyard?

How big a job is replacing head gaskets on a Super V8? - X300

Steel Seal Blown Head Gasket Fix Repair Sealer - 6

Steel Seal Blown Head Gasket Fix Repair Sealer - 8