If it's clicking the starter relay is probably ok. With a wooden mallet or soft hammer tap the piggy back starter motor solenoid firmly whilst someone else turns the key. This will often loosen same stuck by light corrosion.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone