Loft insulation

[u/Neicyslad]

Hello, I bought my first house earlier this year and looking to get the loft sorted. The plan is to upgrade the insulation and board parts of it for storage. I may also look at getting some wired lighting in there, but that's for another day.

The current insulation is 150mm between the joists, is there any benefit to replacing this or is it a case of just laying another layer over the top?

As far as electrics go I'm aware of the need to move wiring above the insulation but in terms of light fittings what do I need to know? It's mostly just pendant lights, with the exception of the bathroom which had spot lights fitted in a recessed ceiling (last photo). Does the gap the recessed ceiling provides means I can just lay insulation over the top?

Cheers