I think it strange too. According to Blake, Avon had been meditating on his scheme to alter the running logs of the London for 4 months. Yet, at the start of the scenario, it looks like it
moves right from the end of the Way Back. I mead were they in those seats for 4 months.
The only other theory is that after Blake has his first chat with Jenna, Vila and Nova about seizing the London, we see said ship flying through space in a couple of shots. Maybe this is the 4 months of time passing. This could have been done better I think.