Botrytis on strawberry plants/fruit

I have struggled with strawberries in pots & baskets for some years so two years ago bought 3 raised beds to put over an old (6ft square) pond that we had covered in decking (but not filled in). Of course it had been emptied first and we've never had a problem with it. It's about 3 feet deep. We have grown other fruit and veg on it in pots successfully for about 10 years, but I needed somewhere better for my strawbs.

The raised beds have wooden sides and are abt 25 cms deep. I filled them with a mixture of soils/rotted manure and bought new plants in autumn 2023. In spring 2024 they all took off very vigorously and I did think I had over-crowded them a little. It seems I was right. They all developed Botryitis and the fruit (though plentiful) was covered in it.

We did have an exceptionally wet spring/summer so I assumed it was bad luck. I consulted a couple of online sites for advice, cut (and burned) all the damaged parts and thinned them out considerably. I didn't take any runners at all. The websites said I didn't need to change the soil/compost, so I didn't. It had already cost me a small fortune!

This year the botrytis is still there - not as bad as last year, not on all the plants, but THERE.

Should I have replaced the growing medium? Did I have the wrong mix of stuff in there? Should I have chucked all the plants even after cutting down?

The beds drain well BUT cos of the wet weather last year I wonder if the damp from the old pond below has caused the botrytis to develop and it's still lurking there?

Any advice gratefully received.