I don't think it has to be same day but a connection (so less than 24hrs). I used the CCR at T5 before flying to VIE earlier in the year, we'd arrived at LHR the previous day in F from DXB. Check-in and CCR staff seemed fine with it. Then again those who take more than the occasional glance at this forum will know there are some lounge dragon training issues at T5, maybe this was a 'bank error in my favour'...it just wasn't presented that way.