junction box wiring

Hi I am having Air Condition installed and have the units already in place now ready for the power. Given the consumer unit is on the opposite side of the house I have run 25mm plastic conduit from one side, through the roof and to the other side. Within it I have two 4mm twin and earth cables...

So my kitchen removers (Who thought they was good at electrical's) decided to cut some wires which they though were for the cabinet lighting. (Mostly correct) however they have cut 1 line leading to another function. What is the best way to extend this white cable (See picture) so that it ends...

Hi I hope someone could help explain in simple terms what I am struggling to understand. I had an extractor fitted about 5 years ago but speed was always slow (dimmer light switch fitted). I replaced the GU10 50W with LED 5W and they always stayed lit even when switched off...I think even the...