This site is should hopefully validate as XHTML5. There is also a chance that it won’t. The temptation to try something new is always present and what better site to screw up than your own . . .
Content Management System
The site lives in the very wonderful SymphonyCMS, a content management system built around an XML/XSLT workflow.
The serifed headings and some subheadings are in Cyan, a typeface derived from the Roman square capitals on the inscription at the base of Trajan's Column. Robbie de Villiers who started Wilton Foundry designed letters with both upper and lower case variations. Lower case letters are not common in the other variations of Trajan that exist.
San-serif headlines and details are set in Underground, a typeface designed by Edward Johnston and Richard Kegler and commissioned in 1916 by London Underground Railways for use in signs. Originally called "Underground", it became known as "Johnston's Railway Type", and later simply "Johnston". P22 Type Foundry created a digital version.
Body copy set in Palatino or failing that Times New Roman or whatever manky serifed typeface you have on your viewing device.