I found it in a charity shop, but was disappointed to find out that it was the 14th in the series...As I've read only the first 2 so far, it will take a while until I can read it!! In the meantime, this is what I found on the Davis' official homepage on this novel:

"Beer but no oysters… It's holiday time for Falco and Helena - until a character he had disposed of reappears, dead, and causes a diplomatic incident. Naturally Julius Frontinus and Flavius Hilaris are thrilled that they have Falco on hand to sort it for them.
Although Londinium is at the end of the world, it's attracting all kinds of entrepreneurs: the best kind, the worst kind, and lawyers. Most of the streets are not even paved, yet they are as mean as in any city where the bad guys think they own the place. Bad women lie in wait as well, and some of them already know where hard man Falco has his soft spots. With an angry wife, a moody sister, Maia's increasingly dubious suiters, and a fractious Petronius, Falco has enough to contend with. Then he gets lumbered with an outraged king, a traumatised orphan, corruption, inefficiency, and British fast food outlets.
Plus Chloris. He knows Chloris. He knows her all too well.
Personal tragedy and political crises vie for the attention of both Falco and Petro, the one with a job he doesn't want, the other with a task he can't admit, and both dogged by faces from their past…
This is the one where travelling to do the research was particularly costly, time-consuming and exotic!"