Where to find a flattering christening outfit for a petite size 14

[dymantisparkelhorniments]

Hello lovely ladies,
I have been given the task of finding an outfit for my mum to wear to her great grandchild's christening.
She is 5ft size 14 with a tummy and large chested.
She thinks she would like some nice trousers and a blouse.
Anyone have any ideas of where to look?

Budget? Colours? Prints or plains?
Hobbs, John Lewis, Romans (I think that's the name).

Jumpsuit with a jacket might be an option too: www.johnlewis.com/browse/women/petite/womens-jumpsuits-playsuits/_/N-flsZ4bsv

She would quite like white or cream pants. I saw these Marks & Spencer but I am struggling to find a nice top. Budget is not huge.
She is 74 so nothing too 'out there'

https://www.marksandspencer.com/single-pleat-wide-leg-trousers-with-linen/p/clp60775773?color=IVORY#intid=pid_pg2pip48g4r4c3

Those trousers also have a matching jacket, so a colourful blouse could work. OR, a similar coloured top with a coloured jacket. The model has a matching, cream top in some of the pics, but I can't find it on their website. I have a huge bust and always find a V neck is most flattering on me.

I'm not sure if this is too white and could clash with cream trousers?https://www.marksandspencer.com/pure-cotton-broderie-tie-front-blouse/p/clp60781989?color=SOFTWHITE#intid=pid_pg1pip48g4r9c2

I've occasionally got nice tops in Tesco, Sainsburys or Morrisons. I don't know if they do a petite range though, but might be another option to get an affordable blouse or jacket.