Algorithmic penalty perhaps but what is it?

[SamCUK]

The keywords aren't particularly difficult to rank for and are in the 30 - 50 % keyword difficulty using the SEO moz keyword difficulty tool. I have ranked these same keywords for other sites I operate without too much of a problem. That's why I'm so confused as to what's happened here. I'm sure its something on site.

[jesse-landry]

gosh i don't know what to tell you honestly. i can't really continue exploring your site for fear someone will walk into my office and wonder what the heck i'm up to...

but let us know if you ever figure it out i'm curious and good luck.

[MarieHaynes]

If your page is adult in nature then it's possible that Google has taken it out of the "Safe Search" index.  I believe the filter is set to moderate tolerance for most people.  It's possible that the latest crawl saw enough adult content to put it in the "non safe" area.   Try changing your safe search settings to show everything and then see if you are ranking.

There could be other issues but without having a good look at the site (which I really don't have a desire to do) no one will be able to say for sure.

[SamCUK]

I don't think it's related to adult safe search as still doesn't show when I change the filter. struggling with this one!

[SEOAndy]

found the problem I think.

Malware found ona  few pages on your site

http://sitecheck.sucuri.net/results/www.top-10-dating-reviews.com/

[SamCUK]

Thanks for that. There's nothing showing in webmaster tools with regards to malware but if that's the case I'd better get to fixing it. How do I go about it though?

[SEOAndy]

you don't want GWT to show it you want to catch it first

find the offending code and delete it, its from an advert or affiliate site of some kind - could be a plugin sneaking it in - it's happened to me before on WP sites a plugin updates and brings bad code with it.

[SamCUK]

The code it's suggesting is malware is code I put on the site myself. As an affiliate it generates a pop up box for people to click and go to the external site. I want to keep it if possible so I'm not sure in fact that it is malware. How's best to proceed? Like I say there's nothing showing up in webmaster tools as malware.

[SEOAndy]

remove it temporarily and see if it fixes the issue? many an affiliate site have been caught loading malware on to devices by this kind of means - be careful

if you find the problem goes away great, contact the affiliate partner and ask them what is going on and to fix the problem - you won't be the only one in this boat i'm sure

[SamCUK]

Will do. many thanks for your help. Hope that's the problem!