Many thanks for the comments and suggestions; I got a little build time over the weekend and investigated the unglued-plank issue more fully.
There are only two bays with planks with unglued edges - roughly the motor location area where the botton is concave and the planks twist a lot.
I have: determined to use diluted PVA, and add horticultural fleece patches to the inside at the same time. I'm not going to use tape on the outside because I need the planks to move during the Squoodging process - I will clean up the outside with a wet cloth while the glue is still wet, and check from time to time to make sure that no more has appeared.
BTW - I don't suggest that what I'm doing is the best or only way, just that I have done it in my mind, and expect that I can follow it thru without drama. There is an aviation saying "Don't let the plane go anywhere your brain hasn't gone 10 seconds earlier"
So progress: Finished the bow blocks - basically cut out any areas which were not solid and bow-shaped and glued in (PU) balsa block, then cut/planed/sanded to shape
After prelim smoothing
And the transom doubler - 1/4 balsa - was PU'ed onto the ply transom, and when dry planed/sanded to the complex radius-reducing-to-nothing shape required
I also found the plans (loud cheers) and bravely cut out the formers in the hatch area, but havn't glued the hatch-forming structure in place cos I need the access for the plank repair operation - for which I need the right trousers (breeks with nothing to lose!)
AND I cut out the motor mount plate - from Satsuma ply. It is just resting in place at the moment and the motor sits on a blu-tack mounting bracket just to get an idea of the drive train in place - All looks OK to me at the moment
Rudder, FWIW, is home-made from bits I have.
Blade is 1mm brass from Proops 1pound box - shaped generally as per plan,
Stock is two nesting brass tubes the outer of which fits the commercial tilller arm
Rudder tube is a length or radio aerial tube (chrome-plated brass which is a good fit on the stock)
Whole shebang soft-soldered together
Prop shaft, etc is Graupner nickel -plated with 4mm thread and 35mm racing prop to begin with
I can see this on the water
andrew