Thanks to @RichardR, I decided to go ahead and report my stuck authorisation at Boots to the in-app chat. They fixed my balance in minutes, which is great and well beyond legacy banks, but the ‘how’ makes the data messy.
Instead of simply removing the stuck authorisation they gave me a ‘refund’ for the amount which shows up at the top of the feed and changes today’s spending in the report. Also, who knows what will happen when eventually the transaction falls off?
It seems one improvement would be to simply delete the authorisation from view.