Thank you
@Roselina, I read this last night and it was exactly what I needed to hear and it helped calm me down.
@Lady Kelly it hadn't even crossed my mind yet so thank you for flagging, I made sure to mention it when submitting the claim and our insurance provider is arranging for an assessment.
The update is that we've contacted everyone today and the car purchase is still on. The dealership will handle the repairs themselves - apparently there's some electrics relating to parking sensors there, they needs a hands-on check to confirm any damage - and liaise with the insurance company with invoices etc. Insurance-wise, because it's so obviously not our fault not only is our no claims discount going to stay intact, we don't even need to pay our agreed excess. Still going to be expensive in the short term but hopefully we will get everything back.
@Sar, I've been having the same problem plus apparently when I'm half asleep and stressed because the baby won't sleep, my childhood habit of biting my nails resurfaces. As part of some enforced self-care I went and had a manicure for the first time ever a couple of weeks ago and apparently applying cuticle oil can help strengthen new growth - not sure if it's true, but. Having some gel nail polish on has really helped stopped my nails from breaking, at least.