Can you let me know if the deluxe awning room and the awning alcove will attach to this 2.5m awning with light kit please?

You'll need the 2.5m awning room and the 2.5m awning alcove and it'll all fit together perfectly.

https://www.arb4x4.co.uk/arb-4x4-deluxe-awning-room-including-floor-2500mm-x-2500mm (awning room)

https://www.arb4x4.co.uk/arb-awning-alcove-xcsa813209ps (alcove)