The handrails on the aft deck should be exactly 1 metre in height on the real vessel. You can work out the scale by measuring their height from the model. A 6ft figure will be approx 1.8 x that measurement.
Thanks guys that's most helpful. The aft rails in the kit are 50mm so using 1.8 rule that means the figures are 90 mm which puts them at 1/18th scale 3 1/2".
All I have to do now is find an outlet which won't cost an arm and a leg (to be glued on. my sense of humour)
I found some 100mm figures in the toy section of the Kmart, that's a little bit big, but a bit of work they many work and at $7 for 3 or $2 for one a good price.