registration not working with captcha

-- HikaShop version -- : 2.4.0
-- Joomla version -- : 3.4.1
-- PHP version -- : 5.4.41
-- Browser(s) name and version -- : Firefox
-- Error-message(debug-mod must be tuned on) -- : No error message just doesnt work

I had a problem with customers not being able to register on my site. I had key captcha installed disabled it and the registration form worked.
So I replaced the key captcha with the recaptcha plugin downloaded from the hikashop site, installed as per directions and find that the same thing is happening with it - when the captcha is active the registration form does not work. I have now unpublished the recaptcha and the form is working but my form is not protected.
I have checked and I believe it is installed correctly.
Strange though in my Joomla configuration for captcha there is only two options (a) use default; and (b) None Selected so I am wondering if this is some of the problem that there is no real captcha defined, though the plugin v2 downloaded from hikashop is enabled. I will leave it up for a few hours as it is the early hours of the morning here in Australia - so you can take a look.

Please can you help
Sandra

Thank-you Nicolas -No the joomla recaptcha is not on. I have just tested it again and it appears to be working.. Quite a few hours ago last night (its morning here) I noticed that recaptcha (where I get the keys) said code needs to be put into the header of the template , I thought the plugin would automatically do that, so I looked in the source and it was not there. So I added the google code into the header.
It did not work straight away but its working now a few hours later so it may just have been a cache issue after i added the code.
I will get back if I have any more issues.
The problem with not showing a captcha in the global configuration is still there, and same with user manager. Cant figure that one out!
many thanks
Sandra

in System/Global configuration/Default captcha the option is there to choose from captcha's that are installed. The only options I have is "none selected"
In user Manager the only option there for captcha is "none selected" or "Default captcha" I thought this might have been the problem.

Does that seem strange to you?
Sandra

Ah OK I see.
I did end up having more problems over the last couple of days with customers not being able to register again, and same when I tested so I have removed the code I placed in the head, and it seems to be working again. Seems to be a bit intermittent for some reason.
Also I find when the registration is successful - a small message comes up at the top of the page saying that an activation code is being sent to the email address on the form.
I find that this note is not very prominent and could be easily missed - is there a way to move it to the center of the page?
Secondly it is not visible for very long before it disappears so longer showing of the form would be good also.
Any help or suggestions here would be great.
Sandra