How can I change the map and start location in the UAV Package Delivery Example?

This can most easily be achieved with a MATLAB script. The example code below changes the map to a location in London. 

%% Change lat-lon used by QGroundControl map
dict = Simulink.data.dictionary.open('uavPackageDeliveryDataDict.sldd');
sect = getSection(dict, 'Design Data');
latlon = getEntry(sect, 'uavIC_latLon');
 
% Set lat-lon to London, then when you simulate with QGroundControl
% connection, it will show London map. You can then use QGroundControl
% to create and upload new mission in London
setValue(latlon, [51.5072 0]);
 
%% Change initial world position used by low-fidelity model during Simulation
lowFiPlant = 'MultirotorModel/Inner Loop and Plant Model/Low-FidelityModel/Quadrotor Plant';
% Check the world position parameter in block mask
open_system(lowFiPlant);
% Change initial position
set_param(lowFiPlant, "InitialWorldPositionMultirotor", [-60 -182 0]);
 
%% Change initial world position used by high-fidelity model during Simulation
highFidelityInitialConditions = getEntry(sect, 'initialConditions');
ic = getValue(highFidelityInitialConditions);
ic.posNED(:) = [-60 -105 0];
setValue(highFidelityInitialConditions, ic);