From what I know pubs try to work off a 65% margin and off-licences a 30% margin. So if you were able to produce and wholesale a beer to a pub, while still maintaining an operating profit level, for 2 euro, the pub would be selling it at 5.70.
My advise would be (once you have your exceptional product) to bottle and sell to the independent off licences. This will create an awareness of your product.
Its all well and good for pubs to take on a keg, but it is the public that will make or break your business, so make sure they know it and like it first:)