At a guess, one of a batch new to Go-Ahead London Metrobus. Probably being refurbished by Thorntons, Ashington for Carousel Buses.

Always baffles to me why they have the second generation Citaro as a Mercedes Benz O295 Citaro in the UK, yet in Mainland Europe it's known as the Mercedes Benz O530 Citaro C2.

BTW for info the range design is as follows....

Mercedes Benz Citaro (Original)
UK - https://www.flickr.com/photos/gjm-photog...0597640072
Europe - https://www.flickr.com/photos/gjm-photog...0588325366

Mercedes Benz Citaro (Facelift)
UK - https://www.flickr.com/photos/gjm-photog...4080032666
Europe - https://www.flickr.com/photos/gjm-photog...2182774250

Mercedes Benz Citaro C2 (Second Generation)
UK - https://www.flickr.com/photos/gjm-photog...5397831032
Europe - https://www.flickr.com/photos/gjm-photog...1667672387
Basel Front (customer made front originally for BVB Basel, but used by a few others, like in Japan) - https://www.flickr.com/photos/gjm-photog...1675589700

Mercedes Benz eCitaro
UK - https://www.flickr.com/photos/gjm-photog...4522457984
Europe - https://www.flickr.com/photos/pieye/51758989358 (Photo by Pi Eye)