All's well that ends well
In the end, the stretcher wasn't used. The milliner actually took The Hat apart and rebuilt it last night. (Which, given that she didn't leave here until gone nine, will give you some indication of how committed she was to having it ready on time.)
One photograph has been taken on my mobile phone so that I will be able to work out where the front of The Hat is (you may laugh, but I have little experience of formal chapeaux) next Friday.
I reveal this fact to you only to taunt you, you understand, as I won't actually be publishing any photos on Lady Bracknell's blog until after the investiture ceremony. Er, and The Hat has been professionally packed away in its box, and I dursn't take it out again to photograph it myself in case I haven't the skill to re-pack it securely.
By the way, I ought to mention that something very odd is happening with Blogger comments just at the moment. Apologies if you've made comments and they've taken an age to be published. Blogger either doesn't email me at all, or emails me about the same comment several times. I'm hoping it's a temporary aberration.