I shouldn't be gobsmacked at how badly they've handled this but I am.
All they had to do in September was to announce energy support. They would have been flag waved on.
Everything else could have been left to a November budget with a full forecast, lots more trailing of policy shifts, comment pieces in the Mail & Telegraph to signal change in direction. BoE would have been able to plan around it etc.
It would still have been messy and Labour would have been able to knock holes in the arguments. But the catastrophic market shifts would have been more limited.
Hubris.