Yes, it looks likely that I will need to use "rel= canonical" tag which is far from ideal.
At the moment we are writing lots of new pages, for example, this page has recently been launched on the .co.uk & .ie websites:
http://www.avogel.co.uk/health/fibromyalgia/
http://www.avogel.ie/health/fibromyalgia/
Again if I copy and paste the first few paragraphs of the text on the .co.uk version or .ie as they are the same into Google.co.uk, its the .ie version that appears, you can check it out for yourself if you wish.
Is this a signal that the .ie webpage is getting all the credit for being the source? Even though it should not be an issue as I am using hreflang tags and everything is setup correctly in webmaster tools geographically for both domains.
A plan could be delaying the new pages/content on the .ie website until Google has crawled the .co.uk version of those new pages/content, however doing this will have the same affect on the irish website as it's having on the .co.uk website at the moment.
Thanks