Hi PML50,
Unfortunately it's not just as easy as unbolting the roof, cutting the rubber seam around the windscreen and then lifting the roof off (which is actually how easy it is to take the roof off!), You need some extra metal bits which usually comes as part of an expensive kit (and the price is really the only bad bit). Take a look here:
Exmoor Trim & Trakkers - Land Rover Interior Trim, Hood and Seat Specialists You'll need the canvas / soft back, a strip of metal that goes across each door top, a part that fits along the top of the windscreen, a few hood sticks (which give the soft top its rigid frame) and then there are two other metal panels which fit on the back end of each door. All the necessary parts come together as a kit which costs within the region of £140, plus the canvas its self.
Have a look on ebay, you'll probably pick them up cheap on there, but beware. The sellers will kore than likely not give you the extra bits that you need.
Here's a link if you can't be arsed to type it in:
eBay - The UK's Online Marketplace
Well worth it though I reckon.