JaneV spotted the followup by the East Kent Mercury Newspaper.  It shows Deal Castle looking very colorful with the actors and set filming Little Dorrit.  You can see the pictures and story here.

IMDb poster, steveg 1023 had this to say about Matthew Macfadyen's role in Frost/Nixon.

...I also was lucky enough to see a screening and take part in a group Q&A with Ron Howard.

MacFadyen's solid, but he really is a supporting role in a movie that really belongs to Sheen and Langella. HIs character is very Darcy-ish in the sense that you know there's a lot of emotion brimming under the surface, and it only comes out in controlled outbursts. He serves as a nice foil to Sheen's emphasis on charisma and a playboy attitude.

He gets one of the best moments of the movie, though. It's quick, but I don't want to spoil it.

Secret Life has been nominated in the Television Films section of Monte Carlo's 48th Television Festival held from 8-12 June 2008.  The Awards Ceremony will be held on 12 June at 7:00 pm.

Matthew Macfadyen received a Best Actor award by the Royal Television Society and a nomination for Best Actor by the BAFTA's for his role in Secret Life. 

Interestingly Keely Hawes' Ashes to Ashes (in which Matthew guest starred in episode 7) is also nominated in the TV Series (Drama) section.

Best of luck to both of them! 

Matthew Macfayden, the star of Spooks and Pride and Prejudice, was at the castle for two days shooting scenes for Andrew Davies’ adaptation of Charles Dickens’ Little Dorrit, which will be screened on BBC One this autumn.

That's what Deal's East Kent Mercury Newspaper is reporting. The two days of shooting involved Deal Castle. The article included this wonderful image of Matthew. The newspaper goes on to say "the scenes shot at Deal Castle will form a part of the story-line set in Marseille, southern France".

Well spotted, JaneV!