I don't say your HV isn't good, but for this designe it have a problem.

I try to make a flash / strobelight from a disposal camera, I use the hardware for a long time.
On boats and planes for navigationlights and also lost plane lights.
It works perfect, but wanted the tube flash at the same time with the spark is a problem.
The last couple of days I distroy at least 10 SCR's and I don't know why.
I use allmost the same schematic like we do to fire the SCR into the HV-board.

BTW, maybe the HEX will be mess up into the EXEL-sheet ?
Do you have to compare the HEX files from a good and a bad PIC ?