Clio III Mirror falling unit off

I guess someone else must have experienced this, how best to stick it back on?
The mirror unit is too heavy for normal mirror pads, and I've also tried Loctite special mirror glue (£8 off Amazon) but that was useless.
The whole unit includes the rain sensor and alarm sensor, as well as a heavy mirror; not good to have it dangling by the ribbon cables.
Any assistance appreciated. 2007 Clio mk3.