Hi everyone, sorry for such a late reply, I hadn't realised that anyone had replied to this thread as I didn't get any notification e-mails!
Thank you for all of your advice, it has been really useful
We're certainly going to invest in a play pen, as I really think it will be useful to have somewhere safe to put the baby where I know that Rodney can't accidentally step on him/her!
I'm really glad that you said about not needing a sterile environment Feebs, this makes total sense, and it is certainly a load of my mind knowing that I don't have to constantly be disinfecting everything once baby arrives! My parents have a cairn terrier who sounds very much like your westie, love terriers! I so know what you mean about parents who let their children go up to strange dogs, we get it all the time. Luckily Rod is soft as anything, but I think it's madness, he's a 42kg dog, so it's is not sensible to pet him without first asking if he is friendly, but people let their children do it all the time!
I think we are also going to invest in a stairgate and get our dog used to not following us around the house everywhere, so then when the baby arrives, it will be easier for us to take it upstairs for a nappy change/bath etc without the dog feeling like he has to come!
Ipanema, your great dane sounds gorgeous! My husband really wants a great dane, but I think we will have to wait until our current dog is much older, not sure we can cope with a new dog, a new baby, and our current menagerie!
Blondefriend, that is so sad about your lurcher
We used to have a greyhound, and they are such lovely placid animals, she looks beautiful in your picture. So glad that your DS is okay though, what a heartbreaking situation for you.
Wif- Bear sounds amazing! Don't you just love doodles?! So nice to hear that your son and your doodle are good friends, that is exactly what I want for my LO and Rodney! Definitely going to download the sound of a baby crying, Rodney hasn't had much contact with babies or children, so I think that is essential for us.
Thank you for all your advice everyone, DH and I are really really grateful for all of your replies, and very encouraged! 
xx