this must be Cordia New (or Cordia UPC),
a font distributed with Microsoft Windows (XP, Vista, Win7++)

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I found it using Find my Font - http://www.findmyfont.com

Cordia New is a Thai font that happens to include Arial characters in it to support Latin. The more likely answer is that it's Arial.

thanks so much for your help :)

You are right Mark, it's more likely an Arial ;)

The only difference I can see is that:
a. Cordia New's Latin characters look much thinner than Arial at the same weight (e.g. Normal) and
b. you need to specify a point-size of 20 to Cordia New to match the height of a 14 pts Arial