I work in Chiswick too, Gunnersbury to be exact which is 5 mins past your stop. I currently live in HH but am moving to ED soon. If I'm on the HH - Vic train at 8.39 I'm at my desk by 930 or just past. And that's not a made rush either. Occasionally you get the alarm go off at Victoria but not for long. Forget all there changes and get a bus up Dog Kennel, and get the Den Hill to Vic train.