Hi Andy,
I am probably not the best to ask for information on lowering and raising the mast as I have only ever done it twice - in both directions!
I do, however, have an A frame, which made things 'relatively' simple. It consists of two metal poles, 2.5m in length, 4cm in diameter, with wooden'feet' with ties and inserted into the poles; joined at the top with a bolt. Not perhaps terribly descriptive but I could send you pictures, Let me know if your email is as per the handbook - the webmaster seems to have an aversion to posting pics here.
In addition I have a detailed account - which I inherited - on lowering the mast and could scan and send if required.
Regards;