It will be fine hun, health visitors dont judge (unless they see immediate danger) she wont judge your home improvements at all! I'm the same as you I'm always worrying what people thinks of my house as I'm so house proud, so if we have work done and my things aren't in their place I feel like I get judged lol!
By all means if the weather is nice sit outside! But dont feel like you have to!
I've never had a health visitor come before the baby is born, but I know some other girls in my area who has. When I had my son, my daughter was 2 and a half, she turned up while I was sat feeding baby in my pjs at 3 in the afternoon, toys and stuff everywhere, washing on my table ready to be out away and my daughter was in the middle of being potty trained, as she turned up my daughter ran into her potty (while bottom half naked) and tipped pee everywhere!!!
I had to apologise to the health visitor and I felt so rubbish! But she laughed and said now this is a realistic home with a newborn and a toddler and she loved it! She also couldnt resist pinching a few cuddles of my son while I cleaned up the wee and a few toys and put my washing away.
So... I dont think she will judge on your home improvements hon