Domain migration guidelines

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Dean Morgan: Hi Guys, I hope you can help me with this one...
  
  I have a site, which belongs to a UK based business. In September we performed a domain migration (for the purposes of this example we'll call them old-domain.com and new-domain.com) and followed all the usual best practice guidelines (301 redirecting traffic, updating internal links, completed change of address form etc.)
  
  Originally the site used to rank very well on Google.co.uk for some of our main transactional keywords, however since the migration things have taken a slightly odd change.
  
  One page in particular ('/optimised/page-1') used to appear on page 1 for the main term we wanted (lets call this 'keyword-1') whilst also ranking for other terms ('keyword-2' at position 30), and it's brother and sister pages ('/optimised/page-2', '/optimised/page-3') also fared relatively well.
  
  Now it seems that '/optimsed/page-1' is not ranking at all in the top 1000 results for 'keyword-1' on Google.co.uk, but it is appearing on Google.com at position 45. On Google.co.uk it seems that 'keyword-2' isn't doing as badly and has only dropped to position 50 (from position 30).
  
  The other pages ('/optimised/page-2', '/optimised/page-3') have seen similar changes, but not as extreme and in some cases we have seen an improvement.
  
  With all the changes happening in September, I can't decide if this is a problem from the migration or whether we have been hit by the penguin update that came at the same time (they 2 events where days apart).
  
  So... my question is does anybody know why '/optimised/page-1' could drop so much on Google.co.uk but not on Google.com when we are a UK based business.
  
  
  If any further information is needed please feel free to ask in the comments and I'll do my best to answer.
• 
  Jim Munro: Hi Dean, if you would like to share the domain with the panelists privately please PM.
• 
  Dean Morgan: I'd be more than happy to share domain's with anyone who may be able to help. The only issue I have is that I don't use G+ very often and can't seem to find out how to DM/PM someone (Which is slightly embarrassing)
• 
  Jim Munro: Just open a new post and share it with only one person. :)
• 
  Jim Munro: From the expert panel in this week's SEO Questions hangout on air on 00:02:48 into the YouTube video: https://dumbseoquestions.com/q/domain_migration_guidelines +Dean Morgan
  
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