Sorry, but that's nonsense. The market dropped spectacularly during the new chancellor's not-a-budget-honestly speech. You can't get a better smoking gun than that.
> but Truss’ announcement came in the middle of the worst bear market in bonds for well over a decade
Yes, and she chose to do that. It was amazingly irresponsible. The market response was entirely predictable.
I still think you attribute too much causality to Truss’ announcement. E.g. 1 GBP cost 12.25 SEK 5 days ago (before Truss’ announcement) and now costs 12.22 SEK.
(But sure, Truss’ announcement did cause a temporary slump even in the GBP/SEK exchange rate.)