Have I killed killed this lavender by replanting it in June?

[greenfingerediamnot]

I've just moved my lavender plants from a rectangular planter into a deeper square one. I read later that that might've been a bad move and that the lavender will go into shock. Is that right? Should I move it back into the original planter or leave them alone?

Put it in the shade and let it recover, and don't let it dry out but don't over-water it either.

Well it's only like buying one in a pot and then planting it out in the ground or putting it into a bigger pot or planter.
It's only when you have to dig a plant forcefully out of the ground and potentially damage the roots that it can be a problem. (If you can get a big enough rootball and give it plenty of water it will be fine).
If that picture is the pot you have put it into, I would just put a few crocks underneath to raise it up off the solid surface a bit, for drainage.
Stick your finger 2 inches in the soil every day even if it's rained and if it's dry water it.

No I have moved mine as well. It will be fine.

It's a huge container- used up almost 80 litres of compost. I watered with a hose last night when it was cool and woke to find it was raining! I'll leave it to dry a little for a few days and see how it gets on.

Thank you- good tips re: lifting it up. It's super heavy so not sure how I'll manage it but I'll find a way! I've put some small rocks at the base of the pot for drainage (the pot has only one small hose drilled at the bottom) but when I watered it- no surplus water came out so I hope I didn't over water it in the first place. Unless the hole at the bottom was covered up by one of the rocks 🤦🏻‍♀️ I did have to yank it a little from the container it was in and heard a ripping sound as the roots detangled from the neighbouring plant.

This gives me hope- thank you. I wonder how long before I notice if the plant is happy or not?

Ps. The pot is in a spot that gets a lot of afternoon sun.