I'd verify this directly with TfL or check your mail before stressing too much - a 10-second drift during a turn isn't usually what they're targeting, and they typically give some leeway for unavoidable lane changes. Bus lane fines in London are usually around £130 (reduced to £65 if you pay within 14 days), but they're generally stricter about sustained blocking rather than brief incursions, especially near complex junctions like Piccadilly where turning is unavoidable. If you haven't received a penalty charge notice by now in mid-July 2026, you're probably in the clear, since they usually issue them within a couple of weeks. That said, check your registered keeper details are correct with DVLA just in case something gets lost in the system.