After reading about Air France and Charles De Gaulle airport I am starting to live up to my user name.
My wife is flying from Auckland to Heathrow with Singapore Airlines soon. The same through ticket but she
has to change aircraft and I presume terminals. The terminal on arrival is unknown at the moment but she
leaves for London from Terminal 3. Is the route marked well enough so that she won't get lost? She self confesses
to be not very good with maps
Just to add to this, Singapore will check your wife's bags all the way through and issue her with boarding passes for AKL-SIN and SIN-LHR at AKL.
9/10 they will be able to print the gate for the SIN-LHR flight on the BP when they issue it at AKL (SQ assign gates very early for flights, particularly LHR ones as the A380s they use on this route can only use certain gates at T3).
When she arrives at SIN, she will arrive at T2 or T3. In actual fact, Singapore is all one terminal arranged in a horseshoe shape and you can walk around the whole thing. But it's big, and T2 is the opposite side of the horseshoe to T3.
Gates at SIN have a letter in front of them e.g. B34. As she's leaving from T3, it'll be either Ax or Bx.
Terminal 3 - A & B gates
Terminal 1 - C & D gates
Terminal 2 - E & F gates
If her gate is printed on her BP, then she just needs to follow the signs to the next gate. If not, check a monitor which are plentiful and well located.
If she arrives at T2 (E/F gates) then follow the sign to Skytrain which will take her to T3. If she arrives at T3 then it's even easier. Plenty of shops and restaurants in the 'main' T3 area which is between gates A & B.
Finally, security is done at the gate at SIN which is a good system as the whole terminal building is essentially one big transit area.
It's really extremely easy.