I think we have previously discussed the arrangement of signals similar to 10 and 11. On NR, the rule is that the top signal applies to the left hand route. In the past some railways applied the top signal to the principal route, and this is certainly suitable when the lower arm is a subsidiary. There is nothing to stop a heritage railway choosing whatever rule it likes, but, if the arms are both going to be full size, I would always recommend following NR practice, as many of the drivers and signalmen will be people who also work on NR.
I think the point ends drawn in opposite positions may be the result of part of the track having been (accidentally?) moved on the computer screen, as the curve of 15B (trap) points seems to be sitting on top of the straight.
Numbering the frame backwards may simply be a matter of drawing the signal box upside down - is the frame at the front or the back of the box?
The numbers in the bottom left corner seem to be out of date - I count 15 working levers. I also can't find the 19th lever - maybe it's at the 19th green?

I agree with the DI about "normally off" probably being the wrong wording.
P.S. It looks as if Dom is already dealing with some of these comments, but I'll post this anyway for the sake of the other comments.