I think the key issue here is your use of the word "cheap". There are some good value products to be had, but basically "you get what you pay for". You might also have a look here: http://www.photodeals.co.uk/home.php?cat=9
If there is any chance (I guess that's a "Yes" then?) of wanting extending your use of this kit to taking other than shot's of your kids, I would recommend not going for the "cheapest" you can get. Go for the maximum power your budget allows.
If you don't, I can almost guarantee that in a fairly short space of time you will want to extend your use of the kit, and find that it won't provide the power that you were hoping for. Your only option then is to replace it. Now it may have been "cheap" in the first place, but add that to any replacement cost and suddenly you are paying more than you need to.
However, if this is the only way you are going to progress further up this mountain we call a "learning curve"
- then go for it!
Have Fun!
TJ
PS - Don't touch the Jessops kit, their Guide Number is worse than a speedlight!