Guys need to replace the rear oil seal on the gearbox extension any hints or tips for easy removal. Hopefully with the g/box remaining in the car, just cause I'm feeling lazy.

This is the animal you want 
 

That looks right up the ally. Wouldn't want to get on the wrong end of it though!!

Does the metal ring come out with the seal or is that a part of the extension housing? It seems to retain the seal but it's hard to tell as the new seal isn't supplied with any sort of metal ring so not sure about digging that out or just the seal itself?

Any suggestions most welcome before I have at it. Cheers!

If your new seal doesnt have a metal outer casing it is the wrong seal and wont fit properly.  The rubber coated seals are smaller and come from a wrong listing many years ago.  One is metric, the other imperial. The rubber seal will push in with your fingers with very little resistance which also mean it will probably fall back out just as easily
 
If you use the tool Matt75 suggested you should get your old seal out without too much damage and then take it to your local bearing shop who will be able to match it by measurement.

Cheers Gdub the joys of flea-bay!! Win some lose some.

Quick update if anyone cares...

The replacement seal seemed to fit pretty well, I thought I'd offer it up to see how much difference there was. The seal had to be knocked in to fit so I figured it turns out as the right one after all. Just to be sure I fitted it with a smear of silicon gasket sealant so we'll see how it goes.

Thanks again guys for your advice.