I had this on audiobook for the gym.  I'd read the first in the series and I wanted something fairly light that I wouldn't have to focus on too much and thought this would fit the bill. I guess it did but I'm not going to bother with any of the others. It dragged and meandered and I wasn't invested in any of the characters or the mystery of who had died and who had killed them. I found it fairly twee as well. The recurring joke is the juxtaposition of middle class, middle England with crime and espionage, "let's have a cream tea and talk about the mafia. Oh dear, we've got raspberry jam which is almost as annoying as the gun violence"  it got tired pretty quickly!