Welcome to the SQ board stut
.
The SQ lounge at LHR is excellent, particularly as you will have access to the F side. The Raffles/C side does have an upper level however. There is a small bar menu from which you can order various snacks like Satay etc. There is some building work going on nearby, which is preparation for SQ's (and others) A380's and as a result the SQ a/c is not currently using the nearby gates like it usually does. The work is scheduled to finish early November.
SIN is one of the best airports in the world for transferring but 1h out and 55 mins coming back (if I've read it correct) is tight and your flights will probably be already showing as boarding on the screens. To be honest even with an hour I would try and nip in for a glass of Krug myself (
), and if you get in early it would defintely be a shame not to sample the SKL's in SIN as they are excellent.
Outbound you will have access to the F side of the SKL but just the Raffles side inbound. I think there may be a smoking area in the lounges but if not there is a public one on the lower lever not far from the escalators to the lounges.
There is an SKL in HKG with both an F and Raffles side but unfortunately it's nothing to write home about. It has no windows for a start which is one of my own pet hates. There is a TG lounge that is supposed to be OK but someone else may be able to give you more info on this as I haven't used it. Presume there is a RCC as well ?
However, when I was flying to SFO on SQ in July I used my KL PE card to use the BA/QF lounge at HKG, which is the one KL use and this was much nicer than the SKL IMHO.
Would be very interested to hear what you think of SQ and SIN etc.
Enjoy the experience ^