Verona I'm sorry to learn you have had to close your pre-school, it's always a huge adjustment that needs to be made when we do.
When we were all juggling with the new GDPR rules coming in a couple of years ago, there was a lot of information about retention of records etc particularly as each authority seemed to have differing ideas, so maybe talking to your authority would help, however, if you check out the Resources section on the forum site you will find Pre-school Alliance Retention suggestions and what is statutory and what is not. Surprisingly some records seem to be needed to be kept for a very very very long time😂 I have told my sons that I will leave them to their care in my Will!