Where to look for wedding outfit for 65yr old mother?

[Pannacotta]

Service to be a registry office in September. She has asked me to help find her an outfit, no idea where to start looking. Any ideas please?
She is slim, size 10, medium colouring.
She would like an outfit (not a wedding dress) which she can wear for a blessing later this year.
TIA

Sort of....try this

R Originals v nice but no store/concession here Thanks anyway and to everyone, have lots of ideas now...