Preserved 1978 Sunderland Busways Daimler Fleetline/Alexander 838 (RCU838S) working the free vintage bus service at the North East Bus Preservation Trust's 2007 Seaburn rally.
Yup, spot on - it was the C-LFT Olympians which had the huge front bumpers. 648/9 were on the Economic routes from new, while 641-647 joined them in 1992 to replace some of the SCN-S Atlanteans. I can also remember two of the H-BNL Olympians (675/6) in Economic colours too.
Actually the noise wasn't that bad on the Sunderland Fleetlines (both Alexander and MCW-bodied) - the Gardner 6LXB engine could be very loud especially on United's fleet of Bristol VRTs.