Stagecoach Cambridge is upgrading its City Sightseeing (What there is to see in Cambridge of interest however is beyond me) fleet from 5 Volvo Olympian to Dennis Trident ALX400 (Low Floor) buses.
The first two of these to go topless was 17078/9 - T678/9KPU which were originally the spare general use busses, but were recently deemed surplus following cuts over the summer, and it was decided to cut them. The conversions were done at Lincoln Depot.
Following Stagecoach re-entering the London Bus market, 4 more ALX400 Tridents have been cascaded over to Cambridge:
The 3 X-Reg ones are up with Newcastle for conversion, and 17099 remains at Cambridge, having arrived as a former driver trainer with Selkent, and was very recently given an MOT, but however its future plans are unknown, as the City Sightseeing only has a PVR of 4 buses, having 6 would seem a bit excessive.
Photo of 17099 sat at Cowley Road following its MOT can be seen here: Photo Copyrighted to The Ginger Ninja. Its also to him i thank for some additional information for this post.