What does she want to use it for?
Does she need software and is this part of the budget?
Does she need good battery life?
You will not get a ruggedised laptop at that price. Get a good well padded carry case instead.
I think that you may struggle to get more than 80Gb of HD below £700. 512Mb of RAM is the minimum to accept and you should get a good screen at that price.
If there is a risk of damage then I would want the extended warranty.
Have a look at the Dell 6400
or an Acer
There will be other brands too including Novatech.