Powering down an optima xm6.

What is the best way to power down the above system in order to remove an outside bell box. I have looked outside the control panel and there are no obvious signs of a fused spur. However, on the inside of the control panel on the far right is what appears to be a fuse coming from the main supply. I think this is the fused spur. I can however, isolate the power to the control panel by switching off the respective mcb in the garage. What's the best way?
Thank you for your help.

You can isolate in the garage for the alarm if that what you are doing, considering their is no non fuse spur next to the alarm.

if a permanent disconnect is required, only if the MCB in question does not supply anything else.

No matter what you do inside the main panel the bell box will activate if you cut the power, internal battery, set the panel to Engineer mode and put a ladder up to the box, take off the box lid and be ready to change the link to the by pass pins in the box, I will look for the diagram tomorrow and post here.

Inside the bell box will be a pair of jumper pins with something like "hold off" "by pass" or "battery on" written on the pc board this has three pins and a jumper to short out two of those pins, move the jumper position to "off" this will silence the alarm when disconnected from the panel, within the bell box and alarm panel will be matching terminal blocks, if you are very lucky the description on the pc board for the panel will match the description inside the bell box, if they are the same make it will be easy to just match the connections, if not you will have to consult the manuals for both units to match up the connections, I can probably help with that if you get stuck, one tip is to take a photo of the terminal blocks for reference before you disconnect anything.

Could look something like this.