Hi I'm totally new to web hosting and the more I read here the worse my confusion seem to get?
If I explain what it is I need a web host to do for me perhaps someone would be able to steer me in the right direction?

I wish to have a web site to advertise and sell my goods
I will be hiring cameras
When my clients have used the cameras I want to post the pictures they have taken on a page that is dedicated to them alone (password protected)
So they have full control over the pictures (download, manipulate, delete and email)
The problem I have is that I have no idea of the traffic this will create and I have no idea of how much storage space will be required fro the pictures.
It will of course be vital to me that I have little or no downtime of my site as this could have disastrous affects on my company's reputation and sales.

What kind of web host should I go for?
What should I look for in that host's services?
Is there a host who will allow me to expand my usage at short notice if required?

I'm based in the UK and would like a company that has a local office (London) and can be contacted by landline phone

Thank's for any help or advice
Carole