next door put a boched up fence up with a 2foot gap is this legal i think they are not right in the head

I think the best thing is to talk to them about it

You may well be right about your neighbours mental state.With regards to its legality,it would need to be no higher than 2m unless planning permission has been granted.If it is within this then theres not much you can say.The fact that its a bodge doesnt mean much and your best bet would be to wait for the wind to remove it for you if its that bad.

if they are council tennents then complain to the council coz they wouldnt have none of it, other than that no higher than 19.50 tall