Op there is a contingent on MN who fiercly defend smoke and smokers.
However, whilst its true, of course smokers are allowed to smoke on their own property, its not right, that as a result you are suffering on a very regular basis and your right to enjoy the fresh clean air of your own home, is being trounced.
Yes, of course you can complain and try and do something about it.
We all - all all ALL, have a right to enjoy our own homes, smokers, and non smokers.
In which case contact EH, and you may be asked about diary's. At the very least they can chat with your neighbours about the smoke, ask if there is any way they could change their position ever so slightly and so on.
Often having a third party to intervene can help enormously.
Whilst people are telling you its not possible, it IS op and I know because I have done it.
We had smokers on both sides and it was over whelming.
On both sides I asked nicely if they could change their smoking position, one side very kindly did so, ( they literally moved their table a tiny bit which made all the difference as the smoke often blows the other way now) the others however were rude and offensive.
So I contacted EH, and they had a word, which was enough for them to also - mostly just change where they sit a tiny bit to give the smoke a chance to move elsewhere.
Its farcical isn't it, we cannot enjoy the interior of our own homes, because the smoker wants to preserve the smoke free environment of theirs.
Perverse 
I am an ex smoker op, and I still have the odd one, but far away from other people and esp their WINDOWS.
I just couldn't enjoy the rare time I have one, knowing I was causing someone else - upset and distress.