See:

• https://developer.mozilla.org/en/Command_Line_Options

• http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows
• http://kb.mozillazine.org/Shortcut_to_a_specific_profile
• http://kb.mozillazine.org/Using_multiple_profiles_-_Firefox
• http://kb.mozillazine.org/Bypassing_the_Profile_Manager

I have now got rid of the profile manager window opening before Firefox opens but that is not the problem. Perhaps I am confused. On an older version of Firefox I had an icon on the navigation bat and if I clicked it I was able to enter my details into any kind of form. It is this icon which I want to get back.

You can look at one of this extensions:

• Autofill: https://addons.mozilla.org/firefox/addon/autofill-262804/
• Autofill Forms: https://addons.mozilla.org/firefox/addon/autofill-forms/

I loaded Autofill 3.6 but can't see how to access it. Does it work with Firefox 23.0?

You can find Autofill in the right-click context menu of an input field.
You can also open the Options/Preferences of the extension via the about:addons page.

See this screenshot from the Autofill download page.

https://addons.cdn.mozilla.net/img/uploads/previews/full/56/56132.png?modified=1361446344

sorry to appear thick but where do I find the context menu of an input field?

The context menu opens if you right-click.
In this case you are in a field where you enter text and right-click while the cursor is visible in such an input field.
Then you would see an Autofill entry in the context menu if this extension is installed and enabled.