So, after several months of enforced idleness with this build, I have finally been able to get past the above obstacle. I'm taking a course in guitar building this year (I'll post details in a separate response for those who may be interested) and consequently have access to all of the requisite tools of the requisite size, and was able to take these in to make use of the pedestal drills there.
Additionally, one very useful tip I picked up doing this that will probably of use to others: when drilling your string through holes, in order to get the the best possible alignment on both sides, drill only the outside two holes all the way through from the top; drill the others only half way through. Then flip the guitar over, and using your outside holes as markers, align the centres of the other holes on the back, then drill these from the back to the mid point. In this way, if there is any deviation of the drill from vertical, it will not be apparent from the faces, and there should still be plenty of clear passage where the holes meet to allow the string to pass through. Given the short length of 2.5/3 mm drill bits, this also makes it easier to drill than trying to get sufficient working length of bit outside of the chuck.
I still have to do the widening of the holes on the back to accommodate the ferrules, but I will wait until later to do this so that I can at least get moving with the next stage.
Here are the front and back holes for one of the guitars:
Front
Back
If anything, the alignment on the back is actually slightly better than the front (the G string is slightly off relative to the others), but better that way round since the holes on the top will be covered by the bridge plate.
With these holes now drilled, I can make a start on sanding and first stage of finishing. In order to give greater depth of colour to the grain, I'm going to apply a very dark black stain first, then sand this back to reveal the natural wood again, while hopefully leaving a darker grain line, then set to work with the DingoTone Black Stump. Perfectly timed to coincide with the long weekend .