Cut and clear anything that's on the bed now. leave empty for the winter then rotorvate it in spring and sow in april/may

Did you remove the topsoil? They need poor ground to do well.

The grass has been cut but I don't see how I can clear the ground now without rotovating it.

How mini is mini? What did you try to grow? Was it fertile ground? Have you looked around to see what wild flowers grow well in your area?

Another approach you could try is to raise the plants in pots and transplant them when they are strong enough. Not a lot of point trying poppies though as they grow best in newly turned earth (as in WW1!)

mini is approx. 28ft x 8ft
I planted plugs of yellow rattle and just scattered lots and lots of seeds from packets of wild flowers/meadow flowers.
The only thing I got were about half the yellow rattle surviving. [had some usual weeds that would have come up there anyway]
Yes I suppose it is fertile - how would I know?