Athens no F. I have always found LHR very good - as there are 4 flights per day SIN-LHR//LHR-SIN. Not all routes have first. A380 has 12 suites, 777WR - 4 , 777W/WN - 8
The list of SIN-European ports with First class flights per day (as far as I know):
LHR - 4 (2xA380/1x777WR/1x777W)
ZHR - 1 A380
CDG - 1 A380
FRA - 2 (A380/777WR)
MUC - 1 777WR
MXP/BCN - 1 (5x week 777W)
MAN - 1 (5x week 777W)