What are the rules for "see and be seen" when you suspect a potential conflict in class G airspace?
In the USA, RW aircraft are supposed to avoid the flow of FW traffic and FW traffic have the right of way for landing. 

So I would have descended to 500ft instead of climbing. Slight differences in altimeters make 1,200 and 1,000ft too close for comfort. But  500ft AGL (noise abatement be damned in a safety situation) is a perfectly acceptable altitude in a heli. 

Also, I would have adjusted my downwind so that I was fairly close to the runway where airplanes are rarely found. 

So now I have both vertical and horizontal separation, and I am in a continuous position to land, at my convenience.