It is rare to get just a twin core cable feeding lights. Most extra low voltage lights have pins to connect the lamp where as the low voltage (230v) GU10 type have a bayonet fitting. Maybe you can remember what you removed?
The inverter/transformer is often just pushed lose into the ceiling void and measuring the output from an inverter one often gets zero volts as with no load inverters tend to auto close down.
Only method is to measure with a meter but I would connect a 100W bulb first in case there is an inverter which may auto close down.
Colours mean nothing. Both line and neutral are live wires and with many lamps can be swapped around so common for them to be clear.
Since you say push fit I would expect 12 volt. I expect you will find tucked in ceiling void a unit to convert from 230v to 12v this may be lose and you may be able to get it through the hole above ceiling rose.
Although more likely you will need to lift a floor board.
If it follows regulations it should be assessable but DIY people don't tend to follow regulations so one has to be careful.