Not had the letter but there was something similar with 2008 R32s a few years ago. It's your brakes though, get it in. The car is well out of warranty so mods not an issue. I imagine it will be the abs module they change or check.
As it's a safety recall, they will have got the owner details from DVLA.Are you the original owner?
I wonder how VW were able to find you?
Maybe through dealer service history records....