can anyone advise correct feedback "ettiquette"

[DuffyMoon]

item went missing and seller has sent me a cheque so all well and good - do I leave feedback saying what happened - as in it was a positive negative experience and seller was v helpful

just say very friendly seller and helpful and positive as it wasnt her fault and she dealt with it correctly i dont always mention item lost in post and refund given as it worries me others will pull a fast one on the seller

Yes I wouldn't mention exactly what happenned. Just put something vague like 'friendly seller, excellent communication thanks!' or something like that abd mark her as a positive if you were happy with how she was with you.