If you want a bolted connection but find battery access difficult, you could always fix it on top of the heavy battery cable that is bolted onto the starter solenoid under the bonnet. Then pick up a decent earth for the negative lead from engine casing or any convenient earthed metalwork under the bonnet. Secure the charger’s socket with a cable-tie away from moving parts and water splash. OK it means bonnet will be open whilst connected but less chance of driving out of the garage with charger still connected! (almost done that on occasion!)
Dave’s advice on fusing essential as any inbuilt fuses or overload devices on the Cetek itself will not protect from a fault on the connecting lead when fault current is fed from car battery rather than charger. Chances of a fault on such a short lead may well-be remote but consequences disastrous. My neighbour’s battery once exploded whilst charging and bits were found in all distant parts of his double garage!
