which host servers for higher uk google rankings?

Not quite e-commerce but I do intend on getting the highest google uk (pages
from within the uk) so I can get the most hits and sell the most possible to
my uk client base.

Correct me if i'm wrong, but I heard that if I want a .co.uk website to list
high on google, it HAS to be placed with a hosting company that has servers
from within the UK, is that correct?

If so, how does that work? What if I had a .co.ukdomain name (which i do
have) and I placed it with the americans who have far cheaper and better
spec hosting plans, and it is important that i get listed under
google.co.uk's search engine when the radio button 'only return results from
pages within the UK' .. how does google know?

Also, what if I had the same domain with .com and placed that with a UK
server, and lastly what if i had the .com placed with the americans hosting,
it wouldn't get listed in google UK at all?

Domain registering company I used was123reg based in the UK.

Mike.