ember error "Specified 2.3.0 Installed 2.4.3" on "ember s"

Somehow I've stuffed up my, previously working, ember.js environment.

When I try to start the server I get :

glaucon@polo ~/dev/ember-django-testbed $ ember s

Missing bower packages:
Package: ember
  * Specified: 2.3.0
  * Installed: 2.4.3

Run `bower install` to install missing dependencies.

If I do then run bower install I get this

glaucon@polo ~/dev/ember-django-testbed $ bower install ember --save-dev
bower ember#*                   cached git://github.com/components/ember.git#2.4.3
bower ember#*                 validate 2.4.3 against git://github.com/components/ember.git#*
bower ember#>=1.4               cached git://github.com/components/ember.git#2.4.3
bower ember#>=1.4             validate 2.4.3 against git://github.com/components/ember.git#>=1.4

But after doing that I am still left with the previous error message when I try to do ember s

glaucon@polo ~/dev/ember-django-testbed $ ember s

Missing bower packages:
Package: ember
  * Specified: 2.3.0
  * Installed: 2.4.3

Run `bower install` to install missing dependencies.

If I do then run bower install I get this

glaucon@polo ~/dev/ember-django-testbed $ bower install ember --save-dev
bower ember#*                   cached git://github.com/components/ember.git#2.4.3
bower ember#*                 validate 2.4.3 against git://github.com/components/ember.git#*
bower ember#>=1.4               cached git://github.com/components/ember.git#2.4.3
bower ember#>=1.4             validate 2.4.3 against git://github.com/components/ember.git#>=1.4

But after doing that I am still left with the previous error message when I try to do ember s

I then (as per Running "ember server" fails with error) tried this

$ bower cache clean

followed by

$ bower install ember --save-dev

But still the same error message

Just to be sure I then followed the advice of http://ift.tt/1UlL7Wo and did the following :

$ rm -rf bower_components
$ bower cache clean
$ bower install

And .. still the same error message !

Any suggestions welcome !

---

EDIT

Forgot to put this bit in. This is bower.json

glaucon@polo ~/dev/ember-django-testbed $ cat bower.json
{
  "name": "ember-django-testbed",
  "dependencies": {
    "ember": "2.3.0",
    "ember-cli-shims": "0.1.0",
    "ember-cli-test-loader": "0.2.2",
    "ember-load-initializers": "0.1.7",
    "ember-qunit-notifications": "0.1.0",
    "jquery": "1.11.3",
    "loader.js": "^3.5.0"
  },
  "resolutions": {
    "ember": "^2.4.3"
  },
  "devDependencies": {
    "ember": "^2.4.3"
  }
}