Looks like my Zinnia seedlings. They reseed quite readily. They will grow to about 30 inches and have big bright colorful blooms that draw bees & butterflies. I would suggest spacing them out a little more.

Were there any old stems left standing when she moved in?
I thought possibly Saponaria or Helenium. They also remind me a bit of Digitalis lutea. I think you will need to leave them a bit longer. I thought Zinnia leaves were a more bluey grey and more deeply cut. But that might depend on which species they are.

She could try asking the neighbours if they know what grew there. Mine certainly would be able to say the colour of the flowers if not give them an actual name.

Also color could determine the color of the leaves as well.

Hmm...I was thinking a Crown Imperial Fritillary, myself.

Put me in mind of Sweet Williams

I thought Sweet Williams too!

So - nobody thinks they’re weeds which is good. We’ll just wait and see. Thanks everyone.

sweet williams is a good suggestion, its years since I've grown them. As for it being a weed: a weed is a plant that you don't like/don't want/or its in the wrong place. I have a patch of dandelions in an out of the way place deliberately for the insect pollinators. So they are not weeds. Elsewhere in the garden they are. :o)

I'm growing a few 'weeds' that I actually bought because I just like them - Joe Pye Weed, Butterfly Weed & Common Milkweed which is important to the Monarch Butterfly. They aren't weeds to me.

I do have a large section of garden left completely wild. Leads down to a stream. I have a trail camera set up and have many films of deer, badgers, foxes etc so no doubt there are lots of other creatures at home there.

That is excellent Slimdil. We get the odd fox but we are miles from the nearest badger set.