Volvo MK3s gone, still got Volvo MK4 DMs, Volvo MK4 Striders, Volvo
MK4 DM3500s, Volvo B10BLEs, Volvo B7RLE, and Volvo double decks...

Whereas Merc 0405s and Leyland
Olympian 3-Axle gone, that's the end of Merc and Leyland
buses for SBST.
The only public Mercs that u still get to see will be the SMRT
ones, ranging from 0405s, bendies and OC500LEs... 
Some will be gone pretty soon, such as the first batch of OACs
(SMRT), 425R-441T, but may get an extension though