Mick,

You can probably pick up a reasonable set of scales from a "good" antique shop (not the girlie/jewelery/crockery type shop ). You could probably check accuracy at the same shop if you hunt around for a set of weights.

p.s. Was up around Lake Jindabyne last week and saw a pretty new sloop rigged Mozzie on the shore. I wasn't able to stop and get the build No. Do you have further details ?