If you need MF then it's got be a Wagobox as per post #5, they're the ones that have been tested and certified and have the approval stamp.The wagobox enclosure i have purchased for lighting? is the "Wagobox Light" version embossed on the enclosure but there is no MF embossed on the the inside of the lid or elsewhere.
It is smaller than the normal box but has cable restraints.
http://www.screwfix.com/p/wagobox-light-junction-box/8423fhttp: