Well, I got home last night and couldnt resist having a go. This may be useful for other members but as you can see from the pics above of Freddy's awesome setup is not a 'professional' way of doing things! If I had the slightest ounce of patience I would have waited a week for my press to arrive, but im not so here goes................
I used a variation of Mike's tip with the tube, I actually found a plactic cap that was about 2mm smaller in diameter to the crystal, the cap came from a small leather dye I had lying around and the good thing was it was shallow and looked similar in size/shape to the dies that come with the presses.
Once i had removed the old crystal I sat the Sunnydale place and I could push it in fairly tight with my fingers to hold it in place. Then I put masking tape over the crystal and around the case to avoid any marks. With a pen I made small marks on the masking tape in the centre of the crystal and around the diameter, just to show where the crystal was located under the tape.
I then taped two pieces of thick leather to one side of a vice, the side that the caseback would be placed against, then placed the case and the cap roughly in place inside the vice, although im sure that that would have worked fine, I had a thought that maybe I should cushion the cap against the vice, so I found a 2cm think piece of rubber that I put inbetween the cap and the vice, I have no idea if this was required or not but it just felt 'better'.
Now everything was in place and I slowly, very slowly in fact! turned the handle on the vice, I felt the crystal move and pop in to the case, maybe I was lucky but when I removed the case and took the tape off, it was seated perfectly!
I then greased the case back seal, put everything in place and had a look, wow this crystal is awesome!
The next jobs on the list is a gen pearl that I have on its way to me, the gen caseback I have on order and the gen rubber that should be with me today! It never ends does it!