Can a landlord insist on a forwarding address before deposit return?

Hi
I have two lots of tenants who have just moved out and are awaiting deposit return.

I have asked several times for forwarding addresses and either through non response or excuses such as 'don't yet have one' none have been forthcoming.

I've never had a problem with this before and for obvious reasons would feel more comfortable with one.

I wondered if I can insist on having a forwarding address before deposit return?

Thanks for any advice.