Physical commodity ETC

Assalamu alaykum. Is investing in gold / silver / platinum ETCs backed by physical metals in vaults halal? Is the sharia rule the same for all such ETCs or is it different for each ETC. I have been looking into Invesco Physical Markets plc-Gold Invesco P-ETC - USD ACC and similar instruments for different metals and apparently ETC investors do not have ownership of metals in vaults.
Is T+2 settlement period also fine?
JazakAllah Khairan.

Assalaamu alaykum,

The ETC you refer to must be screened for Shariah compliance before being able to comment.