New rear tub on older 90 truck

Hi all,
I have a chance to buy a rear tub from a defender with the fuel filler behind the rear wheel I would like to swap it with mine which has fuel filler in front of rear wheel question is what is the easiest way to go about it?
Mine is a 1995 90 truck not sure what year the new one is.
I'm guessing the tank is in a new position on the newer trucks?
Ps I can probably get the roof/can as well

tank at rear is TD5 tub. ya probably better off getting a td5 fuel tank and fitting that.

Thanks that was the advice I was hoping for