Unable to install Ubuntu SDK after upgrade to 15.04 from 14.04

I recently upgraded from 14.04 through to 15.04 so I could start working on a scope idea that I had. Prior to upgrading, I had installed the Ubuntu SDK and had it installed and partially working - but I was having issues with emulators and compiling.

It was suggested to me that I should upgrade to 15.04, and I had already been planning to do so, so I upgraded through 14.10 to 15.04.

However, along the way, the SDK was removed. I figured this was just a normal part of the upgrade process, I can just reinstall it when I get to 15.04.

Wrong.

When I run the sudo apt-get install ubuntu-sdk command, I get this output:

$ sudo apt-get install ubuntu-sdk
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 ubuntu-sdk : Depends: ubuntu-sdk-libs-dev but it is not going to be installed
              Depends: phablet-tools but it is not going to be installed
              Depends: qtcreator but it is not going to be installed
              Depends: qtcreator-plugin-ubuntu but it is not going to be installed
              Depends: ubuntu-device-flash but it is not going to be installed
              Depends: ubuntu-ui-toolkit-autopilot but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

I have tried adding the ubuntu-sdk-team PPA via sudo add-apt-repository ppa:ubuntu-sdk-team/ppa, but that gives me the same error.

Output of apt-cache policy ubuntu-sdk:

$ apt-cache policy ubuntu-sdk
ubuntu-sdk:
  Installed: (none)
  Candidate: 1.221
  Version table:
     1.221 0
        500 http://mirrors.gigenet.com/ubuntuarchive/ vivid/universe amd64 Packages

and apt-cache policy qtcreator:

$ apt-cache policy qtcreator
qtcreator:
  Installed: 3.1.1-0ubuntu9
  Candidate: 3.1.1-0ubuntu9
  Version table:
 *** 3.1.1-0ubuntu9 0
        500 http://mirrors.gigenet.com/ubuntuarchive/ vivid/universe amd64 Packages
        100 /var/lib/dpkg/status

What can I do to fix this?

EDIT:

Output from apt-cache policy ubuntu-sdk-libs-dev:

ubuntu-sdk-libs-dev:
  Installed: 1.221
  Candidate: 1.221
  Version table:
 *** 1.221 0
        500 http://mirrors.gigenet.com/ubuntuarchive/ vivid/universe amd64 Packages
        100 /var/lib/dpkg/status

EDIT 2:

Output from sudo aptitude install ubuntu-sdk:

$ sudo aptitude install ubuntu-sdk
The following NEW packages will be installed:
  account-plugin-tools{a} accountsservice-ubuntu-schemas{a} click-dev{ab} 
  click-doc{a} gdb-multiarch{a} libandroid-properties1{a} 
  libcontent-hub-doc{a} libhardware2{a} libhybris-common1{a} libpay2{a} 
  libqmenumodel0{a} libqt5bluetooth5{a} libqt5bluetooth5-bin{a} 
  libqt5declarative5{a} libqt5nfc5{a} libtrust-store1{a} 
  libu1db-qt5-examples{a} libubuntu-location-service2{a} 
  libubuntu-platform-hardware-api2{a} libubuntuoneauth-2.0-0{a} 
  libusermetricsoutput1{a} pay-service{a} phablet-tools{a} python-mock{a} 
  qml-module-qtqml-models2{a} qml-module-qttest{a} qt3d5-examples{a} 
  qtbase5-doc{a} qtbase5-examples{a} qtconnectivity5-examples{a} 
  qtcreator{a} qtcreator-plugin-cmake{a} qtcreator-plugin-go{a} 
  qtcreator-plugin-qnx{a} qtcreator-plugin-remotelinux{a} 
  qtcreator-plugin-ubuntu{a} qtcreator-plugin-ubuntu-common{a} 
  qtcreator-plugin-valgrind{a} qtdeclarative5-examples{a} 
  qtdeclarative5-ubuntu-settings-components{a} 
  qtdeclarative5-ubuntu-thumbnailer0.1{a} 
  qtdeclarative5-unity-notifications-plugin{a} qtgraphicaleffects5-doc{a} 
  qtlocation5-examples{a} qtmultimedia5-doc{a} qtmultimedia5-examples{a} 
  qtquick1-5-examples{a} qtscript5-doc{a} qtscript5-examples{a} 
  qtsensors5-examples{a} qtsvg5-doc{a} qtsvg5-examples{a} 
  qtsystems5-examples{a} qttools5-doc{a} qttools5-examples{a} 
  qtxmlpatterns5-examples{a} thumbnailer-common{a} thumbnailer-service{a} 
  ubuntu-emulator{a} ubuntu-emulator-runtime:i386{a} ubuntu-sdk 
  ubuntu-sdk-libs-dev ubuntu-ui-toolkit-autopilot{a} 
  ubuntu-ui-toolkit-examples{a} ubuntuone-credentials-common{a} 
  unity-plugin-scopes{a} unity-scope-tool{a} unity8-common{a} 
  unity8-fake-env{a} unity8-private{a} 
The following packages will be REMOVED:
  libprocess-cpp-doc{u} libproperties-cpp-doc{u} 
0 packages upgraded, 70 newly installed, 2 to remove and 0 not upgraded.
Need to get 105 MB/119 MB of archives. After unpacking 287 MB will be used.
The following packages have unmet dependencies:
 click-dev : Depends: python3-click (= 0.4.38.5) but 0.4.39.1+15.10.20150702-0~461~ubuntu14.04.1 is installed.
The following actions will resolve these dependencies:

     Keep the following packages at their current version:              
1)     click-dev [Not Installed]                                        
2)     qtcreator-plugin-ubuntu [Not Installed]                          
3)     ubuntu-sdk [Not Installed]                                       

     Leave the following dependencies unresolved:                       
4)     libproperties-cpp-dev recommends libproperties-cpp-doc           
5)     libprocess-cpp-dev recommends libprocess-cpp-doc                 
6)     qtcreator-plugin-ubuntu-common recommends qtcreator-plugin-ubuntu


Accept this solution? [Y/n/q/?] 

EDIT 3: Output from apt-cache policy python3-click:

$ apt-cache policy python3-click
python3-click:
  Installed: 0.4.39.1+15.10.20150702-0~461~ubuntu14.04.1
  Candidate: 0.4.39.1+15.10.20150702-0~461~ubuntu14.04.1
  Version table:
 *** 0.4.39.1+15.10.20150702-0~461~ubuntu14.04.1 0
        100 /var/lib/dpkg/status
     0.4.38.5 0
        500 http://archive.ubuntu.com/ubuntu/ vivid/main amd64 Packages