Thanks everyone, I've gone for CX250.
As JClasstraveller said above, I won't get any tarmac views from the lounge with 256, whereas if I can get to LHR by 2:30pm for 250 I'll at least have 90 minutes of daylight. Also, I don't want a repeat of my last trip on SQ to Mel when I took the ARN-DME-SIN route, and due to bad delays in Moscow found myself with just enough time for a shower once we arrived in SIN.
Just out of interest, before I posted this new thread I did a search and found a thread from last year where a poster mentioned that "256 should be avoided" but didn't say why, and none of the replies shed any light on why the OP would have said this.
Last edited by jdsworld; Jun 28, 2019 at 2:56 am
Reason: Clarifying wording