Downlight Gap

[mike2016]

Hi,

I installed fire rated downlights today below a bedroom. There was electrical wiring directly above the old fittings so I'd to move the hole to fit the new downlight unit.

Now I've a gap on either side and I was wondering what's the appropriate way to seal this safely?

I could cut out a section of plasterboard and reskim. I was thinking of using a small amount of fire rated foam and then smoothing over this & painting. 

Any suggestions? 

Thanks!