Thanks for replies, I also emailed a forum member who has been really helpful in his reply about electric fencing. Thanks Chris. There is also a downloadable .pdf on Rutlands site specifically about fox proofing which shows you how to construct the electric fence which I found helpful. I am going to construct the electric fence around the chicken fence, outside of it seperately as suggested. There are a lot of badgers very close by as well, a big set. I think an electric fence with at least 1.5joules output is going to be necessary and the cheapest way seems to be (ebay?) a second hand Rutland and wire to posts (around run). I only want to do it once really so I want to make sure it is as safe as it can be before getting any poultry. I am also just going to leave it on all the time now. Going to cost a bit more than planned but it will be worth it in the long run I think.
Now I have been told by my neighbour (old boy, really nice chap), my rabbit proofing round the vegetable plot I have put up this week is great - but have I thought about the deer?
Most of it up there is surrounded by a thick wall of blackthorn but clearly more work to do