Thanks bmmoboy!
My theory is some Streetlite's from Potteries, whilst they receive more Enviro 200's instead... Shame, as i liked the idea of Worcester getting another new vehicle type! - However Streetlite's would make more sense given the depot already has them and staff will be used to them etc.
Any news on 69454? - is she back from repaint yet, as shes been OTR for almost 2 months now! And 69455 is presumably in the middle of re-paint having also been away for a month...