In the department of "here we go again", the 51B is being split up between 51B and 51C.
The new route 51B will no longer travel that loopy way around Bawnogue and Lindisfarne to end at Dunawley, but will resume its "classic" route around Lindisfarne and Bawnogue and terminate at Grange Castle Business Park. Service frequency reduced to every 18 to 20 minutes, including peak times.
The newer route 51C will operate via Convent Road, Fonthill Road South (presumably coming near its "classic" terminus at St. John's Meadows), then go via Cherrywood Villas on the Old Nangor Road to also terminate at Grange Castle Business Park. Similar timetable frequency to the 51B.
(Hmm, since the current 51 is a very-low-frequency route that serves areas already served by other bus routes, how come the number 51 wasn't used instead of 51C?)
Link is in pic (hope it wurks).
