Thanks for the kind words everyone - have to say I'm chuffed with how it has turned out, particularly since I think I will get at least 8 full concert sets and 8 soprano sets from the board. The only issue is with bending the sides - even the plainer set took me a long, long time to hand bend.
How does it sound? Well I find it difficult to put sounds into words, but starting from the fact that overall I think it sounds pretty good, the first adjectives that spring to mind are "clear" and "bright" with plenty of volume.
Whilst I have always been pretty happy with the tone from my concerts, they have hitherto been lacking a little in volume.
For this one (and the spruce & London plane example I completed alongside it), I made several changes to previous:
1) Tops thinned by ~ 0.1 mm to ~1.75 mm for the sapele and ~1.95 mm for the spruce (before final sanding).
2) Bridge plates thinned a further 0.1 mm to 1.7 mm.
3) Fan braces stopped short of the lower soundhole brace and tapered away to nothing, where previously they would have butted up to it.
4) Fan brace profile changed from "peaked" to the continuous curved shape I used on a batch of three baritones built earlier this year, which in turn were derived from the bracing I used on my Cumpiano inspired nylon string guitar. Coincidentally, the latest in Pete Howletts truly excellent ukulele club workshop videos shows a similar development.
5) Bridge reduced 6 mm in width (or is that length? the longest dimension anyway) and switched to a lighter, pinless design.
This is the spruce/London plane concert, but the sapele one is the same:
Earlier example for comparison:
So now I'm happy with the volume as well