This is an easier answer. Less personal, and he's admitting to less in the reply since John does know what he's supposed to say anyway.

"Torchwood," he says. "Torchwood Cardiff. And before that, Torchwood London." Don't ask him to list out the positions he's had in the last five years though because before Torchwood he'd been a temp and he'd never really managed to hold anything down long. He probably couldn't remember half the places he'd been even without a blow to the head.