Is it true that access to this lounge is the same as access to the Crystal (CSA) lounge (in terms of airside security)?

I'm flying out of T1 on British Airways tomorrow. I have Delta SkyClub membership which should get me into the CSA lounge, if I can get there airside. But Delta says the CSA lounge is in T2, and it's unclear to me if I can access it from T1. But this thread makes it sound like they are adjacent.

Thanks in advance