I watched a TV show about the Spitfire a while back - the jest of which was that much of the Spitfire was not created in large factories, but rather in small backyard shops and garages - spread all around England and the rest of the UK. This helped keep production going in spite of the persistent bombing.
The US had a similar problem when they started bombing Japan - there were not a lot of big centralized factories but thousands of small shops distributed throughout the populated areas that produced the various war materials (which was used as some of the justification for resorting to area bombing rather than trying to hit specific targets - which it turns out they couldn't hit anyway).