This forum has its moments. Also the order is wrong here, try clicking to reply or add a comment under mine this time to keep the entries sequential.
The Libra shovel is one I would never use for removing docks. It is based on long handled Irish shovels, good for shovelling, not so good for digging out, in my experience. Cost is the same as their Orion spade, all of £130…
The covering ability of ten tons manure depends on its density, anything from a twentieth to a twelfth of an acre at 6" thick. Two to three inches with black poly over is cheaper. A 6" thickness is more viable for smaller and less numerous beds, but you may have access to loads of manure. Apparently one cow produces, with bedding, four or five tons of manure annually.