Chiffchaff flycatching indoors

Chiffchaffs (gransanger) have been flycatching around the Buddleja bush and on the veranda over the last weeks  and I guess it was only a matter of time before one explored the rich pickings on the windows of the living room, also known as my indoors forest garden. This is the inviting view from the balcony looking into the living room with the door open:


Sat at my desk in the living room on the 18th September and suddenly a chiffchaff had joined me and was catching insects inside: