To add on some SMRT bus services
which served long term perm since brand new:-
TIB623K on service 171
>> since 5 Nov 1995 when handed over to
Tibs
TIB481C on service
181/961
>> perm since May 1995 when converted to
PAC
>> this bus was perm KJDEP 181, then WLDEP 181/961 and now
AMDEP 961 
TIB665P on service
160/980
>> since 1996
it was perm AMDEP 160/980
>> xfer to WLDEP in Apr 2000 and became WLDEP 167 perm, but
in Jan 2001 back to perm 980 under WLDEP since
then
TIB922Y TIB923U TIB924S TIB925P on service
853
>> perm since Nov 1998 when newly
registered
TIB907S TIB909L on service 980
>> perm since 25 Jul 1999 Tibs/SBS swop
TIB651D TIB653Z TIB655T TIB660C TIB662Y TIB663U
on service 167
>> perm since 25 Jul 1999 Tibs/SBS swop
TIB958U on service 67
>> since 26 Dec 1999 when handed over to Tibs