Summer work experience for consultancy?

Hello,
I have a few questions about consultancy (either strategy/technology) work experience pre-university (probably going to end up work shadowing).

Would a week of work experience in any of these during the summer holidays before university help with applications for first year internships in consultancy? (Unsure if there's any point or not).

I have a number of possibilities for this summer:
- Deloitte
- PKF Cooper Parry (two weeks is available)
- IBM
- Grant Thornton
- KPMG
- Jardine Lloyd Thompson
- Natwest
- Arup (again... Did a week's work experience here last year, but did enjoy it a bit)

These won't be at the London offices, but will be at regional offices in the Midlands.

I might try asking EY or PwC as well, since I know people who managed to get a week's informal work experience with them last year.

Thank you.

Hang on, have you got offers/ contacts for all those top companies?!!! Wow!

Yes, any previous experience you have will be extremely helpful, definitely go for as much work experience as you can It can help you get a foot in the door if applying to the same company next summer, and let you improve/ demonstrate relevent skills and qualities which you can use on any internship application.

Well, practically all of them are family or school contacts, since most of my family work in the big 4, top 10 accountancy firms, or in banking. Also, my school has links with some of those companies (via alumni etc.) so they give out contact details of people in those firms to students to arrange work experience with.
Thank you for the advice too. I'd better get calling people then.