Ok, some comments on your needs.....
16" doesn't tell us anything....resolution defines number of pixels and such determines how much oomph the system needs.
If ya want light weight and long battery life, you must sacrifice performance.
If I'm doing the math in my head right .... no coffee yet this morning

.... your budget is about $2300
I just bought one of these though mine was configured differently which would break your budget:
17.3" 1920 x 1080 Full HD (16:9) LED Backlit GlassView LCD , Super-Wide Viewing Angles
Intel Core i7-720QM Processor, 1.6 GHz, 6MB Smart Cache
IC Diamond Thermal Compound - CPU + GPU
4GB, PC3-11333Mhz DDR3 - 2 DIMM
NVIDIA GeForce GTX 285M w/1GB GDDR3
500/7200rpm GB SATA-300 (SATA II 3GB/s) with G-Force Protection
Windows 7 Professional Edition 64-bit
4x Max. Blu-Ray Reader/8x DVD±R/2.4X +DL Super-Multi Drive
Intel Ultimate-N 6300 Wi-Fi
Internal Bluetooth V2.1 + EDR Module
1 Year Premium Parts Warranty + 3 Year Labor
# Built-In 2.0M Pixels Digital Video Camera
# Built-In Fingerprint Reader
# Built-in 56K V90 Fax/Modem
# Built-In 10/100/1000 Mbps Ethernet LAN Card
# Built-In 7-IN-1 Flash Memory Reader(MMC/RSMMC/MS/MS Pro/MS DUO/SD/Mini-SD)
# 1 IEEE-1394a Fire Wire
# 1 Express Card 34/54 Slot
# 4 USB 2.0 Ports
# 1 eSATA Port
# 1 HDMI Output
# 1 DVI-I port
# 1 Kensington Lock Port
# Built-in Microphone, 4 Speakers and Sub-Woofer
# 4 Audio Jacks for Line-Out, Line-In, Microphone-In, and S/PDIF-Out
# 100/240V Autoswitch AC Adapter
# Standard Carrying Bag with Strap
Came to about 89% of ya budget allowing room for a few upgrades. This is from a US Clevo distributor....you can find UK distributors here:
http
/forum.notebookreview.com/showthread.php?t=91510#uk
Here'sone:
http
/www.kobaltcomputers.co.uk/g870_overview.php