how deep for onions please?

just under the surface chick

they say the top should stick out the ground but I cover mine up cos bods pull em up. Mind you the mole undermined them and dragged them through his runs and they came up in all sorts of unexpected places
 
the RHS advice is to make a shallow drill and plant em in that, with just enough soil to cover. I think Titchmarsh recommends planting em deeper because of birds.  So not too deep I think is the answer  

Birds seem to be attracted to the brown of the skins and they like to pull the sets out of the ground, so I would suggest that you remove any loose papery skins before planting the sets. When they are planted, the tips should still be pocking from the soil.

Personally, I wouldn't remove the papery covering as this gives the bulb more protection from the damp soils. And definitely net or fleece. As for depth, it seems no matter how deep I set in the seedlings or bulbs, they'll still grow out of the soil where they seem happier so don't fuss too much on depth, just get them covered with soil.

Hmm, I have planted mine quite deep this year, whell half of them anyway, the other half I put into pots to start them off and they really need to go out now but its so blasted cold and wet they'll be staying in the greenhouse a bit longer methinks!