dns-prefetch broken link

First off, I’m a newb…I apologise in advance if I ask/do something stupid.

I have just taken over WordPress and Webmaster duties to help a buddy out who’s in a bind over a little host/webmaster and him parting ways. (At least I can work a keyboard…which is a bit beyond him.)

I notice he has a slew (70) of broken links all pointing to apparently the same site.

When I view the broken link detail it tells me (I’ll spare the whole thing):
…
<link rel=’dns-prefetch’ href=’//www.google.com’ />
<link rel=’dns-prefetch’ href=’//moz.com’ />
<link rel=’dns-prefetch’ href
Link is broken.

When I check the viewsource of all the pages throwing this broken link, I see that the one following moz.com on the dns-prefetch list is always:
<link rel=’dns-prefetch’ href=’www.zippy.co.uk’ />

I am assuming, that zippy link is the culprit.

So I did some web searches and find that dns-prefetch is usually in the Theme functions.php file.

Unfortunately, I’ve been through every php file in the Theme directory and found no dns-prefetch entries…let alone the zippy.co.uk one that seems to be throwing the broken link error.

So can anyone give me a clue where to look to find dns-prefetches other than function.php of a Theme?

Thanks in advance.