Somehow Gollidr died even though he's invincible (he goes into bleeding out state and then comes back to life in about a minute) and I didn't realise for a while. Now I can't find his body anyway and when I use console commands all I end up with is a completely empty body or the default items. How will I get my blades armour back?!

Also when I use the moveto command Skyrim crashes.

I'm not sure if you can get your blades armor that you gave him back in this case or not, but you could use the console to add new copies of the blades armor to your inventory.

Try: player.additem 1 on each of the pieces that your have "lost".

for each can be found http://www.uesp.net/wiki/Skyrim:Specialty_Gear#Blades_Armor.