Hi Claire,
Yes, you will need to make sure the deposit is five weeks’ rent or less before 1st June 2020. You also need to do this if you renew your existing tenancy before 1st June 2020. [Edit: This was wrong.]
You don’t necessarily need to amend your tenancy agreement. But if you renew, then the agreement should describe a compliant tenancy deposit value and a compliant deposit should be registered.
The method for repaying a partial deposit amount depends on scheme provider and whether the deposit is held in an insured or custodial scheme.
I have just written a quick guide to DPS and plan to do the same for MyDeposits and TDS.
Thousands of landlords will be going through the same thing as you, so I’m sure other users will pop in here with help and tips.
I hope this helps!
Sam