Ark I have a friend who was planning exactly like you - first get married, then change the house and then think about babies. So they got married, they got a bigger mortgage and moved into a new place and started to think about having baby. They could not get pregnant and after tests and checkups if appeared that she has quite a few female health issues. Guess what? She was beaten herself up that they have been far too much focusing on material things and now she has health of an old woman and cannot have a baby!
Eventually it all worked out, although she spent in the hospital most of the 2nd half of the pregnancy, and now they have a girl of four. At the same time she is still struggling with her health issues, now more related to the spine and bones.
Remember that whatever happens and whatever you do there always will be something you will think it didnt go right. There are so many couples in UK who would give up everything to have a baby. You are young you have time to get settled.
Just print out a hospital bag list and buy all what you dont have from there, some basic clothes for first weeks of the baby and you'll be fine. Do the internet shopping, saves lots of time and money and you will be all set till end of november. You have a whole MONTH to sort things out!