I changed my boots without upsetting the inner bits at all....
... if you undo the metal rings which secure the inner boot (large end) - (but they may be held in with cable ties or lock wire) - the outer bit of the CV joint will remain in place on the inner shaft, and the inner bit (3 - pronged 'spider') will slide out of the joint attached to the outer shaft. (or it may be the other way round - but it doesn't matter - it still works)
You can lift the outer shaft away and onto the workbench where it is straightforward to swap the boots!
# obviously you will need to undo the hub retaining nut first - which will need a new part on assembly #
If you haven't already bought your boots, I would heartily recommend
these guys - I iknow the listing is for an Elise - but it's the same parts for an elan.
I got 4 boots, 2 hub nuts and change from £20 with next-day delivery
Oh, and once it's apart this way, and you can clean the grease off the shaft, you'll realise that the end bits are held on a spline with a circlip - undo that, and you won't have any drama trying to stretch the new boots over the big bits with a cone - it all just slides on!