When my courgettes get to 2-3inch long the end starts to go brown & then starts to rot any advice would be helpful thanks
It's likely that the female courgette flower hasn't been pollinated - do you have plenty of pollinating insects around your garden in the summer?
This is a common experience, especially early season.
If you put courgettes in the search box, I'm sure there will be past threads where this has been discussed.
Isnt there something when the flower gets wet - doesn't dry out and rots? I'm sure I've heard this on GQT.