dont know how to find and eliminate plugin conflicts

I have vantage premium and all vantage plugins, two issues have arisen: unable to show captcha on the contact form, and other users continual denial of login for user administrators.

I installed this site in a /wp/ folder then moved it up to public_html. first, tried to add really simple captcha, for contact form 7, but the captcha image would not show image on the live contact page. So then I tried Recaptcha, then that didnt work, i.e. no captcha image and unable to submit the form. I then tried honeypot which doesnt need an image, it didnt hide the shortcode from appearing in the form.but at least the form can be submitted. I believe that the shortcode should not be showing, so I wrote to a linkedin wordpress forum and they said It appears that you are loading up jQuery twice. It is already loading up once via the WP standard method (which occurs when you fire the wp_head hook) However you also have this in your header.php:

So he said I have to remove the second version, and that may be the reason for users not being able to log in…. I have had to keep creating new user members with admin rights, to give to my clients, because within a day, their login seems to no longer work. Now this login failure may be due to their browser cache linking to old /wp/. but I do not have the programming or technical skills to find and remove the jquery double up.
It was suggested I de-activate each plugin til I find the plugin that is preventing the captcha image. I did this, but did not deactivate the main vantage plugins metaslider and page builder because I cant imagine they are the cause of two scripts being inserted. but I did deactivate all the rest I had, but to no avail.
I have Black studio tinymce, change memory limit, contact form 7,contact form honeypot, google analytics dashboard, limit login attempts, mailchimp, simple 301 redirects, ultimate social media icons, updraftplus, wordpress importer, yoast seo.
And the .htaccess says:
Order deny,allow
Deny from all

Allow from all

Does this sound like a possible error to you?

URL: http://www.workinghealth.co.nz/contact-us/