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All resolve to www.mysite.co.uk.
I've queried this with Google and their reply is...
"I have reviewed the three 'search term' sites in question
and have confirmed that they do lie within acceptable Google policy as they do not go through a third party redirect."
My understanding is that this is breaking Google double serving policy but I cant see which rule is being broken.
* Indicate who owns the destination URL, but does not need to match the actual destination URL of the landing page exactly.
* Appear to be a viable website address. It must include the appropriate extension such as '.com,' '.net,' and 'co.uk,' but 'www' and 'http://' are not required.
* Represent a website. The display URL also cannot be an email address. For example, 'email@example.com' would not be allowed.
* Comply with editorial policy, which will be discussed in later topics.
Do the URL variations actually work if typed into a browser? If no, then they violate rule #2.
Even if they do work, IMHO, duplicating sites on multiple domains purely for the purpose of bidding on multiple ads should be a violation of policy - but I, unfortunately, can't find any specific rule that prohibits it.
What you would need to find out is perhaps this affiliate is running 3 different accounts using some kind of alias or other client accounts so that they can obtain multiple ads on the same page.
As the previous poster said - this might be an affiliate having multiple domains.