Mandaz, get the biggest you can. I was in size10 maternity clothes all the way through with DS yet I still struggled to fit in size 14-16 disposable knickers! Mine were from Boots though.
With hindsight, I would probably advise any first time mum to buy really cheap huge cotton granny knickers instead. I don't know how high the mothercare ones come up but if I'd have needed a c-section, there is no way that my paper ones would have been comfortable as they sat right under my jelly belly. For the first few days it's like having a water bed strapped to your tummy so you really want someup and overs! 
Congratulations on your neice, Mabel!
Happy birthday for yesterday, Cori!
Normsnockers, The book is called; The Baby Whisperer Solves all your problems (subtitled) By teaching you how to ask the right questions. It's beige and slightly bigger than the blue one. It has a picture of a baby @8mths old on cover sitting in dungarees and a cap! The blue one is more detailed but this one covers all the stuff from birth too just in a more succinct way. I was a 'York Notes' kinda girl even at Uni so this suited me fine!
The blue book has lots of stuff about why babies cry etc and how we need to learn to spot tiredness and hunger. Probably good for a new mum but not sure you need all that second time around.
Re bag for hospital. I have to say I took one small holdall that held everything I needed for both me and baby until we got home. I didn't need to take a towel as that was supplied. In my bag was, socks, slippers, wipes (for bath&baby)) 2 nightshirts, underwear, thin dressing gown and a book. Also snacks for DH & me inc. 2bottles of water. Then I took 4 vests & 4 sleepysuits for baby plus small hat and a blanket. You wont need cardis & stuff for baby as the wards are always very warm. I also took 8 nappies but they only just did me for my overnight stay. DH brought the snowsuit when he came to pick us up.
Don't forget if you need to stay longer your DH/DP/Birth partner can always bring more.
Hope everyone is enjoying the weather. We visited a nature reserve today and DS who is only 18mths walked for a whole hour, refusing to get back in the buggy prefering instead to point out every tree and bird and to pick up as many sticks as his little arms could carry! Needless to say he was fast asleep within one minute of getting back in the car. Bless!
It made me so excitedabout having two.