Hi Victoria - we can't tell you how to complete panel 10 above and beyond the guidance provided online -
Guidance: how to complete form TR1 - GOV.UK
All I can add is that either option you refer to works and the ting to consider is whether you want to include reference to the Dec of T and submit a copy to be on record or not.
If you are completing panel 10 then yes the TR1 needs to be executed by you as purchasers