Sure... You need to download the file above onto your Mac. The file is in Binary so I used the following website to convert it:
http://140.124.181.188/~khchung/cgi-bin/plutil.cgi
I then opened the file on my Mac and copied what was under the 'UK' section of the file to replace what was under the US section. So the US/UK section of the file now has the UK phone formats:
<key>uk</key>
<array>
<string>0### - ### ####</string>
<string>00 $</string>
<string>0## - #### ####</string>
<string>+44 ##########</string>
<string>0#### - ######</string>
</array>
<key>us</key>
<array>
<string>0### - ### ####</string>
<string>00 $</string>
<string>0## - #### ####</string>
<string>+44 ##########</string>
<string>0#### - ######</string>
</array>
Then I saved the file (you don't need to convert back to binary) and reloaded back onto my phone (taking a backup of the original file just incase of problems). Make sure you reboot the iphone and you should now have UK dialling formats..
Mark