The Fitflop ones are ok - functional more than pretty - there are nicer comfy silver flats out there. Cheaper ones too.
The Monsoon ones I dislike (a lot, sorry ...). They look like a little girl's "dressing up as a princess" shoes. Very girly, overdecorated & not great quality.
You're now spending what, about £130 on two pairs of shoes (neither of which you especially like or will wear again, is that right?).
I know I said previously that I thought it a bit daft to spend £175 on the ok-ish but a bit too 30s-replica-style shoes - as I thought you were just buying them for this event & didn't love them.
However, I DO understand your desire to look fab, wearing a pair of gorgeous shoes that you feel great in & make your calves look good (even if no-one can see your calves!!). And you do seem wedded to the idea of some sort of heel for the evening (even if they're not suitable for dancing)?
If so, get some gorgeous heels (walkable ones). But if you're only going to wear them once that still seems silly (even with my profligate impulsive tendencies!!). So I would choose them on the basis of future occasions (however rare) when you might wear them again. A great pair of silver heels & matching bag will go with most "event" outfits. I have a few metallic shoes/sandals/bags combinations, some of which I've had for years - they're fairly timeless.
That way you won't need to panic-post on Mumsnet next time you have an event to go to ... 😁!!
And have a look at cheaper shoes than the Fitflops for dancing in (if you really don't have any pumps you can bring with you & slip into?). The point really is comfort & ease of dancing. That's if you even like the ceilidh dancing - lots of people don't & stick to the disco bit!
https://www.monsoon.co.uk/blair-metallic-ballet-flats-silver-1000706836.html
These are out of stock on their own website, but some on John Lewis & other sites that stock Monsoon. Reduced to £27.
https://www.amazon.co.uk/Fly-London-Womens-Saub268fly-Ballet/dp/B0DBQZHBY1
Depends on the stockist & size, but the silver/black or the spearmint options of these are reduced to as little as £27.
IMO these are nicer & cheaper than the Fitflops (which I know have their devotees but I think they tend to be people who wear them all the time? If you won't, then I'd get something prettier & less expensive).