Arriva have recently received a number of small Optare Solos, as detailed in recent issues of Invicta. 1521 is one of those to have entered service in the 'old' Arriva livery, and is seen here on 23rd January in Quarry Hill Parade, Tonbridge, on Sundays-only route 401.
The route itsself is a Sunday-only hybrid of services 402 between Tunbridge Wells and Sevenoaks, then extending via the Go-Coach 1 (formerly numbered 401) to Westerham, and has been deregistered by Arriva pending KCC tendering from early April.
Chris