Halo is only plug and play in boilers manufactured post June 2019 with the serial letter code AFQ and beyond and 8C.
Independent, Logic, Logic Plus, Logic MAX, Vogue & Vogue MAX, prior to this will require a Halo Smart Interface Bracket, product code 220366 which are currently only available from Ideal Sales 0844 543 6000 or by using their loyalty points.
The Halo interface bracket enables external mounting of the smart interface instead of using the aperture in the front of the boiler.
The bracket is wall mounted and requires power from a 24 dc power supply (standard plug) and wires in to the Open Therm Terminals on the boiler