Its entirely natural to be worried about stuff when you realise you are about to be a parent.
But I do think you are over thinking things and perhaps need to discuss this with your partner and maybe with the midwife as you seem to be over thinking things and bordering on real anxiety about the birth of your child. Perhaps you are focusing on this whole 'bunker thing' as something you could be proactive about when you are feeling a bit helpless about the whole 9 months of waiting and hoping that nothing goes wrong. I know people who have spent the whole 9 months being scared of something 'going wrong' with the pregnancy/baby instead of enjoying the pregnancy. You cannot prepare for every possible emergency. Lets be honest, you are more likely to be hit by lightning than be involved in a nuclear war. WIll you stay indoors for 9 months 'just in case of storms'?
Nowhere in Scotland would you get a school to build a bunker! We live near a nuclear power station and we dont have one 
TBH you wouldnt want to survive as others have said. Read 'The Road', you wouldnt want that for yourself or your child. Its the most depressing post apocalyptic book on the planet and unfortunately pretty close to what the world would be like.
Relax, enjoy the fact you are going to have a baby soon, being constantly worried isnt helping you or your partner. Yes do something you enjoy, if you want to get back into a gun club then do it, but not because you feel that you need to protect your family in the event of war, but because you enjoy the sport. LIve in the here and now not in some imagined future. If there was a nuclear attack and it dropped a few feet away from your house all that preparing would be in vain anyway.
Hey you live in Scotland, its Gods Country so you will be fine
(thats a long standing joke btw not a criticism of anywhere else, and I am not even religious!)
Anyway far too many bampots, terrorists got their just deserts last time ( a good kicking) they got the message!