Thank you Colin Bishop for your advice. I'm afraid I have no knowledge of how one would do "scaling up", though I think i remember from technical drawing lessons at school all those years ago that it was a pretty tricky business, but perhpas some kind of CAD package can facilititate this nowadays ?
I wonder which of the two, i.e. the Dave Milbourn, and the older plan 1061, would produce a more asthetically pleasing boat ? My ideal is in fact a Spearfish, but there are no plans for that boat (as a model), so i was going to build a Huntsman 31 and make it rear cockpit etc.
I have read that supposedly the Spearfish was taken from a Huntsman 31 hull, at first I accepted that on face value, but on reflection, one is a 30 and one a 31, though I appreciate that that may just be marketing / labelling and that they may indeed be the same, though there again, I have noticedd some line drawings on the internet that appear to give the Spearfish a slightly shallower forefoot.
By the way, what is going on with the text box that one types one's replies to on this forum ? It is grindingly, heartbreakingly slow. I have taken to writing replies in notepad and pasting the entire content into the reply box.