When I took the noon SQ flight LHR-SIN in F, there was a menu in the F Lounge which had ramen noodles, sandwiches, and some other items (sorry, I cannot remember what they are) which can be ordered from the Lounge attendents, in addition to the offerings at the self-help bar. Since I arrived early at the airport to see off my sister on a different flight that morning, I was at the lounge in the early morning and aside from breakfast items, there was congee available at the bar counter.
I am sorry that this does not answer your question directly but I hope it helps.
Cheers,