They weren't spare vehicles for Discover. The original PVR for the three routes required 12 former Airport Flyer Eclipses, the three Solars (65724-6) and needed two additional older Eclipses. Subsequent to that, the Eclipse that had gained the heritage Badgerline livery (66726) was repainted as a spare. However, service revisions late last year and now the cutting of one of the three routes means that they have become surplus.
The three Solars were the only examples in the fleet. Having been on the Majeski express service in Reading, they then did a spell on the X74 Slough to High Wycombe. They then did a stint at Weymouth for a summer (IIRC) but then came on loan to Bath although were based at the Westbury outstation. They then stayed with two Eclipses heading the other way; one of those odd First transfers!!! 65726 gained Urban colours, with 65724 getting them after a serious RTA and rebuild. 65725 retained Barbie throughout until all three gained grey eLeather seats, USBs and Discover livery about this time two years ago. They're nice machines despite their age.