That plan is 1:96 31" which would make scaling up relatively easy! BUT it's very limited (possibly the same as the S Models
"Waverley: The last paddle-steamer on the Clyde, built in 1947 and in use in 1993. Scale 1:96, length 31in (787mm), hull beam 3.75in (96mm). Lines and external details only."
If you search 'Waverley' on the CMB site it produces two more plans, both with much more detail and info apparently.
Thought this query sounded familiar Martin (W)-
Some links for lots of original pics in the thread😉
Scroll down to near the start.
A guy called davidhgreatbatch has one in his Harbour on this site.