I did a bit of investigation and came across this page,                                                                                                        

http://www.laptopjacks.com/view_part/LG-Laptop-DC-Power-Jack-LG41225.html

Part Number: LG41225
Center pin diameter: 2.5mm
(and lists my laptop there as LG P300)

However my laptop has 5 contact points whereas that picture only has 3.

I then saw this power jack which I believe is the same type,
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=400145746359

What does that metal cover do? For the description of another unrelated power jack, I saw "If your old jack has 3 pins only, you can easily remove the metal shield covering the DC Jack" <- so why do I need it?

meh... any suggestions? I found half of the power jack I need... now it just needs it's winter jacket.