In South East Essex I'm paying £15 for a large rectangular bale or £3.50/£4 for top quality small bales....
Google Don Dear, not the cheapest but they deliver all over and the bales are huge and top quality.
We have just bought in hay for our cattle that is not horse quality from Dougie Hill he is normally competitiive on price and good selection of sizes of bale.
My hay is £3.80 a bale delivered and the local feed shops are selling for £4. Having said that it is possible to get it cheaper, my friend is still sourcing it for £3 a bale from somewhere near Basildon.