I have objects that are in boxes up to 210cm tall by 240cm wide (sometimes even taller and wider for the odd custom order) and about 30cm deep. Up to 150kg each item. Im trying to figure out a safe way for the driver to unload these items at customer sites that do not have a loading bay. Ive seen them dropping them off the edge, which i dont like for the danger to the person on the ground level (among other reasons including manual handling risks). Ive seen them attempt to unload using the tail lift. This has its own problems when the items are so big and they try to balance them when the item can slightly overhang the tail lift. The tail lift also tips forward slightly as it lowers which just means the item wants to topple, the driver cant easily support the heavy items from toppling with their one free hand as the other is used to operate the tail lift. They cant be put on pallets as they cant be stacked without damaging the product so they have to be stored on their end. So that rules out using a truck. Trying to find a way that is the safest possible for manual handling, for the person assisting at ground level, and the safest for our drivers. And i would really appreciate some suggestions or examples of how others handle such situations so i can improve the situation for our team. Many Thanks in advance for any help! 

They are very large mattresses. In boxes measuring regularly 210(h) x 240(w) x 30cm(d). And weighing up to 150kg each

My last round of mattresses were not boxed (obviously buying the cheap ones from major manufacturers).

The driver however did not work alone they had a mate (not quite the 150Kg being described) but as a bulky King size it did need two people to lift from the van and in to the house.

I am surprised you have dismissed trucks - there are variations on a theme and on at least on occassion a delivery turned up on what is termed a stair climber sack truck (set of three wheels each side like a fidget spinner rather than a single one) which had an outrigger so the load was slightly angled but required no support.

You could also consider panel shifters as examples (no affiliation) https://www.armorgard.co.uk/prod/loadall

https://www.martincontenedores.com/gb/1853-board-truck-800x380x900-mm.html

Or simple beam bogeys https://www.armorgard.co.uk/prod/beamkart

​​​​​​​Your problem seemed to be offloading the mattress from your original post, you could use something like this.

https://aldeagroupuk.com/product/liftmate-ki-400-manual-stacker/?attribute_pa_lifting-height=1200mm&utm_term=&utm_source=google&utm_medium=cpc&gclid=EAIaIQobChMIqZyDvqGO_wIVyYBQBh1rzAttEAQYCCABEgKAvvD_BwE

However, it may weigh more than the mattress as I could not see the weight of the unit.

Just a thought.