Garden light connected to main lounge light stopped working

I have recently moved into a new property and all light fittings came with no shaders/were pretty basic. I have then proceeded to (safely) remove the light fitting of the living room, replaced it with a proper pendant lamp, and reattached it. It works well.

However, since doing this a floodlight in the garden (sensor activated, halogen) stopped working. The floodlight comes with a switch to turn it off completely, I checked it is in ON position and the bulb is not damaged (tested it on a different lamp).

The builders confirmed the circuit/cabling of the garden floodlight is connected to the one in the living room but refused to articulate any further.

A look at the living room light fitting shows the current situation:

To illustrate better, here are the cables getting IN the eight holes (pardon the terminology):

BLUE (to lightbulb) BLUE empty empty BROWN BROWN BLUE BROWN (to lightbulb)

There are also two spare cables, one blue, one brown, hanging forlornly by the side:

I half suspect these may be those giving electricity to the outdoor light, but as I have done enough damage with my first intervention, I turn to you for any indication of what may be wrong with this/where I should place those two leftover cables.

Thank you for any help!

Edit: I am in the UK.