I mamaged to get this big lump of metal (no idea what it was) but it is pretty big and heavy so i think it would make a good first anvil but I am not sure how best to clean it up, i was thinking of angle grinding it to a smooth surface and laying on a log with something through the centre hold to fix it in place. 

I have several pictures including a tape measure for size. 

Ps could the pointed end be rounded off for a makeshift horn?

That is a bull set. Think of it like a 8lbs + chisel with a wood handle attached to it. It is used to break stone. You have one person using the handle to hold it while the striker strikes the bull set with a sledgehammer. I use this tool regularly in my everyday job. I don't know what steel it's made of but it's tough. It will of been hardened and tempered originally but work would of possibly work hardened it also. I would clean up the edges of the face and use it like a Nepalese blacksmith using a sledgehammer as an anvil. Here are some picks of the one I use at work.

I was rather hoping I could have it horizontal to make use of more surface area. But I am guessing by having more metal undercmy hammer it becomes more stable and useful right?

Not more stable but more efficient.

You only need a working surface as big as the hammer you are using. Maybe make a tube stand where you can flip it over and use either end as needed.

Im sure it doesn't matter a whole lot if your gonna use it as a hammer. But you did make mention of cleaning it up. 

If you want the rust gone; Get a 5 gallon bucket, a 12V auto battery charger and some Arm and Hammer super washing powders. Use them to do the electrolysis method. I recently did this to remove rust from an old 2LB Hammer head and two sets of tongs that were absolutely covered, and it worked great!

Or you could dump it in a pail of plain old white vinegar overnight and brush the stuff off under running water in the morning.

Does such a good job that the bare metal will start flash rusting after it's out. So be prepared to put your prepared finish on it. (me it;s generally BLO, paraffin wax; or paint.

I had thought about using that process as well Thomas. If he does, will he need to put baking soda on the bare metal before finishing it? I heard that you need to do that to neutralize the acidity of the vinegar to stop the process. But I have no clue if you oil, beeswax, etc. if that will stop the process as well. 

`Overnight in vinegar => scrub with a scrub brush under flowing water => dip in baking soda solution =>  rinse in flowing water => dry => finish!