LHR T2 only opened recently, so I'm hoping that the DC website is just out of date ;-)

I've got a Canadian DC (issued by BMO; no outlay on my part as it's provided by my employer - but we don't get DC points for some reason..) but and have had no trouble accessing the lounge at T3 (or any of the listed lounges i that I've visited to date using the card - only in North America, apart from LHR, though)

If I end up at LHR early, I may try and explore - will report back if I discover anything worth sharing!