Thanks for the suggestions all - I think I've finally figured it out.
Stripped it down again yesterday and decided to use some different wire as suggested, just in case. when I was tightening down one of the post screws I noticed it gets snug and then loosens off again, like the threads were stripped/slipping. Changed it for one of the spare screws and luckily that tightened down fine, so presumably a dodgy screw rather than stripped post threads.
Fingers crossed, its been stable for the last 12 hours or so on this new build, so hopefully that was the issue!
I can finally enjoy the flavour on this thing, which is excellent
Next thing to look at is finding a drip tip that fills the top cap. The standard one is short and leaves a gap under it which seems to fill up with juice/condensation in no time at all. Luckily that's a minor issue which I can live with in the short term though.
Stripped it down again yesterday and decided to use some different wire as suggested, just in case. when I was tightening down one of the post screws I noticed it gets snug and then loosens off again, like the threads were stripped/slipping. Changed it for one of the spare screws and luckily that tightened down fine, so presumably a dodgy screw rather than stripped post threads.
Fingers crossed, its been stable for the last 12 hours or so on this new build, so hopefully that was the issue!
I can finally enjoy the flavour on this thing, which is excellent
Next thing to look at is finding a drip tip that fills the top cap. The standard one is short and leaves a gap under it which seems to fill up with juice/condensation in no time at all. Luckily that's a minor issue which I can live with in the short term though.