Ceiling Rose

[RF Lighting]

That's because maintenance free junction boxes don't require maintenance. Ceiling roses have screwed connections which may come loose, so do require access.

It's so much easier to do it right and properly by disconnecting the existing ceiling rose, feeding them through a small hole in the middle of your polystyrene feature, and then reconnecting the ceiling rose, than having to buy and faff about with MF junctions which may still ultimately go wrong.

 

[PrenticeBoyofDerry]

If I was to install a maintenance free (MF) junction box in the ceiling void (as suggested earlier in this post) and glue the ceiling rose (polystyrene one) over it, the terminals won't be accessible.

The reasoning behind maintenance free methods of connection are that they do/should not need any maintenance, therefore their terminals are not required to be accessible. The MF junction boxes do not have the standard screw tight terminals, they are pushed in and gripped by a tension gripped spring, therefore reducing the possibility of these connection becoming loose through expansion/contraction/vibration and any possible accidentally pulling of the cable.
Just make sure you have configured the conductors correctly and have correct continuity have polarity and that the conductors are gripped securely within the terminal before you glue up the feature ceiling rose!
Also note that the MF box does require a little more bare conductor on the conductor end to make good contact to the terminal, this does not mean bare conductor should be visible, just need to make of the ends a wee bit more for good contact!

 

[PrenticeBoyofDerry]

There is an article here in "wiring matters" which covers MF connections.
MF juncitons
It is PDF downloadable file!

 

[Launchbury]

Fantastic. Thank you very much for your help.