on their website (google singing hands), you can see a couple of youtube clips of the new DVDs - you could take a quick look at those (although not much use to you since you've already ordered!)
imo, it's one ofthe least annoying nursery rhyme/singing dvds that dd has - I've heard it at least 4 times a day for the last 2 years, and I still don't want to throw it out of the window 
seriously, it really quite tuneful.
a nice selection of tunes, some unusual ones I hadn't come across before etc.
they also say on their website they are doing another episode with Mr Tumble - hurray!