The Adventures of Isabel by Candas Jane Dorsey

I WAS PERSUADED - PROVISIONALLY, WITH CONFIRMATION TO BE GIVEN ONCE I SOBERED UP - TO GIVE UP MY CAREER AS A CALL GIRL AND BECOME A DETECTIVE.

When a good friend's beloved granddaughter is murdered, an ambisexual downsized-social-worker and her cat, Bunnywit, are enlisted to help solve the case. For the police, Madeline is just one more dead sex worker - so it is down to our hero and her friends to uncover what happened. (Though not the cat. The cat mainly sulks.)

With humour, sarcasm, and a good dose of irony, our protagonist swaggers through the mean streets tracking down leads to get the bad guy. But what at first seems an average street killing is actually the surface of a grandiose and glittering set of criminal schemes that could mean far more trouble than she signed up for...