Sadly, this practice of building the body around the tanks is common.
There is a story that is supposed to be True about Henry Ford, They brought him a design for a new carburetor I forget how many screws but he took one look and said "TOO MANY SCREWS" and tossed it back,,, So they revised, the new one had only 4 screws.. His response was "Still too many screws" The final design had but a single screw you removed to clean the carb.. He liked that one.
My observation: In the 1970's I could change a heater core on my wife's ltd by simply clamping the two heater hoses (Hemostat style) and removing them from the core, Remove oh, about a dozen screws, lift the lid, the insulation, the core, drop in the new core replace insulation and lid reconnect hose,unclamp, start car and top off coolant.
Now, this is for a more modern car,, Ford product
Disassemble passenger side of dash.
Evacuate air conditioning system
Disconnect A/C lines at firewall and cap off
(Offically you drain the cooling system but everybody just):
Clamp heater hoses and disconnect at fire wall.
Slide air conditioner evaporator out on it's rails and lift core out from behind it.
Re-assembly is reverse procedure.
Of course it could be worse: Renault: REMOVE STEERING COLUMN
I kid you not.
My theory: they get a bonus for making it hard to service so the service technicians can work more hours and the dealers make more profit on repairs.