BRP return post T2(G) renewal

[gsp]

Hi All,

I have recently renewed my T2(G) visa for myself and dependants, though separately. In my letter it clearly stated that my old BRP should be returned (or else will be fined) to a specified address which I promptly did. However in my dependants letter it didn't say anywhere that they should return the old BRP. What should I do in this case? Return the old BRP cards to the address that I sent mine to be safe? Appreciate any advise.