After posting the first overhaul of my RH strut I have now completed my LH strut as well and with the benefit of hindsight here are some tricks.
1) Gently heat the top cover to melt the loctite and the top cover comes off with almost no resistance - the heat needed is not even enough to blister the paint.
I was advised to use a chain type pipe wrench and after some difficulty I obtained one but as it really puts most of it's pressure on only one area I feel a normal stillson type pipe...