Since nobody answered...... These photos don't show what looks like mold/mildew to me. 1st and 4th photo made me think of spider mite damage or even possibly thrips. 2nd photo looks like insect damage (possibly flea beetle). 3rd photo looks like a fungal issue. Last photo looks like leaf miner damage.

Thanks Party Music, I think I'll chop/dispose of the worst bits (past flowering anyway) and monitor the rest. Spider mite only usually a problem in as the usually cool UK weather keeps them in check.

Looks almost like sunscorch on the first pic, but not on lower pics. What has the weather been like?

None of it is mildew. Remember you had almost the hottest temperatures ever in July, plus a long period with no rain. Stuff has suffered and is easy pickings for pests and diseases.

Is that a wild flower collection you have there? Do I see campions? Ox eye? Knapweed, perhaps? The foxgloves look no worse than usual at this time of year. Cut them right down or even chuck them. They're biennial or short lived perennials and never last long.

In fact I'd cut them all back if perennial and chuck completely if annual. Natives don't flower for long periods and traditionally would have got the chop at hay making. Pic 5 appears to be black nightshade which is a weed. Ditch it. In future water if we get another hot dry spell. And I wouldn't hesitate to compost it all.

How encouraging. It's piddling sown today for a change but I will chop the digitalis which is biennial but provided a sea of seedlings. And yes, I don't mind a bit of Oxeye daisy and even thistles and nettles which others consider weeds. Good for the beasties which I tolerate. Thanks.