From experience, be aware that some (maybe just the more expensive
directional type) light fittings have gaps between outer housing and bulb
mounting.
This allows all manner of creapy crawlies, likely attracted by the light in
the first place, access from loft space to kitchen (or in my case bathroom).
I made some covers for the "backs" of my fittings to keep these critters at
bay and also stop insulation covering them.
Is there no way you can accommodate a hatch?

Phil