It's him all right, though I think not w/ Diana but Mariana
That is, I think the woman in the picture might be [link|http://sv.wikipedia.org/wiki/Mariana_Simionescu|his first wife, Mariana Borg (née Simionescu)]. (Sorry, couldn't find anything on her in any other language. Well, OK, there'd probably be something in Romanian...)
Here is [link|http://www.aftonbladet.se/kvinna/0405/02/SONDAG-02s48-bjornmariana-557_368.jpg|a picture of Björn and Mariana] from a Swedish tabloid. And here, if you scroll down to the end of [link|http://www.tennis-histoire.com/champion-borg2.html|this (French-language) biography of Björn], there is a colour photo. She has at least as charming -- and distinctive -- a nose as the late mrs Windsor, IMO.
[link|mailto:MyUserId@MyISP.CountryCode|Christian R. Conrad]
(I live in Finland, and my e-mail in-box is at the Saunalahti company.)
Ah, the Germans: Masters of Convoluted Simplification. — [link|http://www.thetruthaboutcars.com/?p=1603|Jehovah]