The message
from Janet Tweedy contains these words:

What annuals/half hardy annuals can you sow now to fill in gaps?
I have tried cornflowers, Godetia and thought I might try poppies and
cosmos.

Would Osteospermum be quick enough?
I have dug out a new large bed and it would be nice to 'fill in gaps'
until I have planted shrubs.

Bit late to get them to flowering this season, surely? I think I'd
compromise, sow some red and green lettuce to fill a late summer space
in an ornamental way, for this year, and some biennials such as daisies,
foxgloves and sweet williams or wallflowers for next season.

Janet