UK Car Repair Questions? Ask a Mechanic for Answers ASAP
Are the lock cylinders seized? In an emergency you can connect a jump box to the starter terminal and to ground, just as if you were jumping the battery. Or you can use a thin shim to pry the upper rear corner of the door open slightly, enough to insert a long bar with a hook end, and pull the interior handle to unlock the door.
if you can unlock the trunk with the key, you can also drop the rear seats if they are not locked, or go through the "pass through" with a long hook rod to release the lock button or pull the handle