I've had my Mini 3 Pro for a few weeks and really enjoying it, but very much lots to learn!

Flying it last night, i had a couple of issues:-

1.  Zoom not working - I tried zooming in with the wheel but seemingly didn't work (had worked earlier in the morning)
2.  I had some odd issues for a while in standard mode where it seemed to be jerky, i would fly forward, it would move a little then stop, then move again, but seemed very sluggish and a lot slower and very stop start.

Any help gratefully received!

For the zoom issue,  zoom depends on which mode you are in, for example in 48mp photo mode its disabled.

I would fly forward, it would move a little then stop, then move again, but seemed very sluggish and a lot slower.

I had something similar twice with the Mini 3.  Both times I attribute it to false signals by the Obstacle Avoidance (OA) system.  At the time I was flying toward the direction of the sun when it occured.  I put it into Sports mode, which turns off OA, and no further issues.  

Hello there Bossy. I am sorry for the trouble this has caused and thank you for reaching out. It is possible that when your DJI Mini 3 Pro is facing directly to the strong light, it would trigger obstacle avoidance mistakenly. So you might need to avoid flying straight to the sunlight, or you can switch off the obstacle avoidance system, but need to be more careful when flying your DJI Mini 3 Pro to avoid any unwanted incident. Thank you.

Why aren't you using the correct DJI Mini 3 Pro forum?  
Then it will be much easier to find your request...