The reliable way to hire a tradesperson

Hi, we've a dark blue wall that we want to change to dark green. Have been advised to use a grey undercoat over the blue to help block it out. We were sold dulux trade undercoat in grey but it says for use on wood/metal before high gloss paint. Is that ok as an undercoat? It's a Lick paint we intend to use. Many thanks.

Hello, I recently bought a property and was changing out the spotlights to LEDs. I noticed in most of the lights upstairs, the loft insulation is inside the recess. In the loft itself, from what I can see there's nothing around the light to keep the insulation away. Is this a fire risk?

I have a bare brick extension that will eventually be a kitchen. What is the best way for this to plastered. Plasterboard and skim or sand/ cement then skim?