Well done Mark! Good sound advice.
Given that not many of us are going to sign up for a 5 day industry course on how to winch safely - which, if you were working for a major company, you would probably have to do in order to get a proficiency certificate (as an example google All Terrain Training Ltd and look at forestry winching courses) -
here are a couple of really useful downloadable guides to the subject:
1) HSE Guide to Debogging and Recovery of Forestry Machines
www.hse.gov.uk/pubns/afag703.pdf
2) Forestry Commision Tech Guide FCTG001 Winching Operations in Forestry - tree takedown & vehicle debogging
www.forestresearch.gov.uk/pdf/fctg001.pdf/$FILE/fctg001.pdf
Both these include excellent sections on how to plan the job and select tackle, and are well worth a read - far from scaring anyone off, I think they will inspire confidence by providing a lot more understanding. They are the best written and most practical HSE documents I've seen for a long time, a lot of care must have gone into producing them.
Another point worth clarifyng - it has been stated that a Matador winch is rated at 7T and the Breaking Strain of the rope is 18T, the Explorer is a 12T winch with 22T Breaking Strain rope.
Winch ropes for industrial applications (e.g. forestry work, mobile cranes, excavators) are selected on SWL (Safe Working Load), which is determined by applying a safety factor. For winch and mobile plant applicatons this might typically be 5-1.
So a rope having a breaking strain of 18 tonnes might have a SWL of only 3.6 tonnes. (18 divided by 5), the SWL of the 22 tonnes breaking strain rope would be 4.4 tonnes. This presumably applies to situations where Health and Safety legislation is enforcable.
Note that breaking strain is a design figure - the rope will not necssarily fail at exactly this point - the failure load coud be lower....
Talk to your local wire rope supplier for proper advice - the usual Blue Peter disclaimers apply to my scribblings.
I replace my MV winch ropes with the original spec (or higher spec if one is available), the cost is not horrific and I know they can be relied upon.