Hi Ruben,
Thanks for your reply. I hadn't even thought about whether the .eu domain could be having an effect so it's good to get a different view point.
I just did an incognito search in Google FR, Google DE and Google ES for the term 'boiler hire' and they rank 4th (for the .com domain) and 6th (for the .co.uk domain) across the board. We actually fair worse in all of the above search engines than we do on Google UK.
In answer to your question though I can't think of any instances where I've seen a .eu domain outrank a .co.uk domain in the UK. Has anyone else ever encountered this?
Thanks,
Ryan