If I was looking for a quality premium VPS provider from the UK, who would you be looking at?

I’m searching for one that offers, speed, exceptional server and network uptime, and problem free hosting.

I have a few in mind from what I have being reading on here from the last month or so, and from sending emails out.

This VPS would be for hosting a design clients database driven website.

Cpanel and WHM only.

Managed preferable, as I have other commitments and want to be able to send a ticket in when I need a issue sorting, a fast response rate. I don’t think I’ve seen a VPS that does end user support, it be nice but not a deal breaker. As to the managed, while Root is nice to play with, I probably wouldn’t deviate from the providers set up.

Specs?
I want it to be fast enough that it can handle several high quality company websites, and while database driven they don’t have forums or such, as they are business sites, spam email and abuusers not a great issue.

It needs to be fast enough in ram and specs that it can run these sites pretty well and handle a increase in sites without slowing much aand needs to be able to be run cpanel/whm. Going by this I presume (and correct me if wrong) I need a VPS with a 1024mb minimum of ram? Suggestions on this would be fine. The specs also need to be able to be increased as I develop

Thoughts?