Webmaster message - increase in 404 pages

[dentaldesign]

I've had a message in webmaster tools:

Increase in “404” pages on http://www.ethicaredental.co.uk/There are 1000 pages in the crawl error list. But all of them direct to t a 404 page, i.e  http://www.ethicaredental.co.uk/search?searchword=toothwhich, which as far as I can tell has all the necessary features of a good 404 page (clear message saying the page doesnt exist anymore, navigation, and business details.The webiste was built in Joomla previous to a re-design in Wordpress. Is this a Joomla issue?  How can I satisfy webmaster and Googles crawl to understand these are decent 404 pages? Or dop all 1000 pages need to be 301 redirected.??Any thoughts appreciated

[Mobilio]

As long as you return 404 this is good. But the question is "why search results in CMS are indexed?". And answer of this is "Joomla". I will keep them as 404.

But there are other 404 pages there:
http://www.ethicaredental.co.uk/download.php?f=tombolis-article.pdf <- http://www.ethicaredental.co.uk/download.php?f=tombolis-article.pdf
http://www.ethicaredental.co.uk/download.php?f=ethicare-dental-ad-april-2009.pdf <- http://www.ethicaredental.co.uk/download.php?f=ethicare-dental-ad-april-2009.pdf
http://www.ethicaredental.co.uk/download.php?f=ethicare-dental-ad-may-2008.pdf <- http://www.ethicaredental.co.uk/a-one-stop-shop-for-oral-health-needs/
http://www.ethicaredental.co.uk/download.php?f=how-i-did-it.pdf <- http://www.ethicaredental.co.uk/how-i-did-it/

Few domains that didn't exist anymore:

file:///Z:/Clients/Current%20Clients/Ethicare%20Dental/Articles/JULY%20ARTICLES/Is%20the%20new%20best%20toothpaste%20in%20the%20world%20all%20its%20cracked%20up%20to%20be.docx <- http://www.ethicaredental.co.uk/is-the-new-worlds-best-toothpaste-all-its-cracked-up-to-be/
http://www.hypnotherapydunstable.co.uk/img/dentist.jpg <- http://www.ethicaredental.co.uk/taking-the-fear-out-of-a-trip-to-the-dentists-chair

Few 301 that i would skip:
http://www.ethicaredental.co.uk/orthodontist -> http://www.ethicaredental.co.uk/orthodontist/
http://www.ethicaredental.co.uk/hygienist -> http://www.ethicaredental.co.uk/hygienist/
http://www.ethicaredental.co.uk/finance -> http://www.ethicaredental.co.uk/finance-and-guarantee/
http://www.ethicaredental.co.uk/zoom-tooth-whitening -> http://www.ethicaredental.co.uk/tooth-whitening/
there are much more i just show 3-4 examples.
And few more small issues. This is result of direct crawl now on site. If there was link as:
http://www.ethicaredental.co.uk/blah-blah
that i can't see it now anymore and it return 404 now. I would 410 it to prevent deleting them over and over from SearchConsole.