happygareth

Looks like Blossom Bottom Rot. Don’t let your soil dry out if you can help it. Easily recoverable on further fruit if treated.

Blossom Bottom Rot is a calcium deficiency which can be cured by frequent watering. So less water more often is better than a good soaking once per day. If you aren’t able to prevent your soil drying out then I presume adding Calcium magnesium (cal mag?) should also help. I’m certainly no expert but that’s my understanding.