I just want to say, thank you very much for the responses, the welcomes and the links.
It is rare to encounter a forum in which people are so courteous, patient and knowledgeable - often, those qualities don't sit together, but here they do. This is a good forum.
I will certainly be browsing the information.
I think for now I will give up on incubating and just buy some chicks or laying hens instead, but probably in a couple of years I will have another go at hatching eggs, once I am more experienced and knowledgeable.
Thank you.