So you now have your acers in ericaceous compost. They also need to be is an area which is not windy and does not get direct sunlight from 11am - 2pm in summer. Whether in containers or the ground they will need a lot of water for their first year - if you are in an area of hard water then it really needs to be rain water.

Why don't you join GoY, it is free, and then we can help you more as you wil be able to answer our questions.

After the winter when they are dormant they will probably recover and start in the spring with new growth, once you have burnt this seasons leaves they wouldn't recover, hope they look better next year.

Ive never heard this about no sun between 11.00am and 2pm Moon grower? I have two rather large Acers in the border which I wish would stop growing!! I might have to re-home them, they get the sun from first thing when the sun is in the East and again as it comes around the bungalow from the West , I have one in a raised border that gets the sun all day, and was doing fine until I planted a phormium that seems to be getting very big and must be taking the water and neutriants as it is looking a little sparce this year! but it was planted over 10 years ago before we moved here and only this year it looks sad.

Maggy if they get plenty of water acers can cope with being in full sun but they prefer not to be. As Guest's acers have already been stressed it is wise to take extra care of them. Hope you don't have to move your acers once they reach a certain size they are not easy to move.

Also, Maggy, from your description, it sounds like your Acers are already getting just the sort of sun that MG recommended: sun in the morning, then again after the hottest part of the day.

Many Japanese maples can take full sun, especially the purple and green leaf varieties. The variegated and translucent varieties much prefer dappled shade. The biggest problems with Acers as Moon grower suggests is a lack of moisture at the roots, especially when young. That's why they can be problematic growing them in containers, Because they can dry out too quickly.
Removing all the old compost is not a good idea this time of year when roots are actively growing. All I can say is good luck, I hope they recover.