If it was an old GM small block or something I’d say just drain the old gas, refill it, and away you go. 
But for a Jaguar V12, the tolerance for bad gas is likely low, and the cost to fix it could be exorbitant. 
So if it were my car, I’d do a full fuel system colonoscopy: drain the tank and have it cleaned (can be done DIY, but do your homework due to the fire hazard), disconnect the fuel lines in the engine compartment and blow out the old gas, and finally replace the fuel filter. 
PS: it looks like the fuel pump is external to the tank. But I would assume there is some sort of pre-filter (“sock”) on the pick-up that is replaceable. 

If the car was sitting for that long without fuel being drained the gas will have turned into foul-smelling varnish. You need to drain the tank and clean it internally. Dropping it for a good cleanout would be the best approach. The entire fuel system will need to be cleaned as well. (You're on the right track replacing the fuel injectors.)

how full is that gas tank? If it’s not very full, you can try diluting it with new fuel; I believe it’s something like at least a 5:1 ratio new to old is optimal. Scotty’s friend in Albuquerque, Bernie at Automotive Test Solutions (ATS) makes a fuel system cleaner. That might even clean your injectors so you don’t even have to change them.