I seem to have come across a solution for the UK number formatting problem.
Using the information from Wikipedia on the following page:
http://en.wikipedia.org/wiki/Telepho...General_format
I have altered the US section of the ABPhoneformats.plist to look like the following:
<key>us</key>
<array>
<string>0## ### ####</string>
<string>00 $</string>
<string>01### ######</string>
<string>01709 ######</string>
<string>0114 ### ####</string>
<string>01302 ######</string>
<string>01#1 ### ####</string>
<string>011# ### ####</string>
<string>02# #### ####</string>
<string>03# #### ####</string>
<string>05# #### ####</string>
<string>08## ### ####</string>
<string>07### ######</string>
<string>+44 #### ######</string>
<string>+44 1### ######</string>
<string>+44 1709 ######</string>
<string>+44 114 ### ####</string>
<string>+44 1302 ######</string>
<string>+44 1#1 ### ####</string>
<string>+44 11# ### ####</string>
<string>+44 2# #### ####</string>
<string>+44 3# #### ####</string>
<string>+44 5# #### ####</string>
<string>+44 8## ### ####</string>
<string>+44 7### ######</string>
</array>
This makes UK phone numbers format themselves within your contacts list and also when you enter them into the keypad. Give it a try and see!!
This is only my second post although I have been an avid reader of the forums for some time now.
Enjoy!!

