You switch back and forth between tense again here. Is it intentional?
This location was not coincidental, as his firm was developing trading and banking online application, for exactly this cliental base. Today’s software launching will determine John’s future with the firm. Success meant prestige, an assured continuance of the London based project and a nice five figure incentive bonus; whereas failure would most likely send him to
switch of tense. "he would" rather than "he will".
Perhaps "as if she was aching for a lay-in herself"?
it was aching for a lay in herself
A Brit wouldn’t say this, then or now. S/he’d say "got".
So far so very good. A couple of cultural criticisms aside, your style successfully captures the character and cadence of this genre. I’m looking forward to reading on.
Eric was fast beginning to think that, after all, this job was not for him.
