Yes I do get off the ground but I don't bend my knee's anymore then is shown in the video stills. There is a little bend but its know where near enough. Its definately one of the things I need to work on. I think the little bend I have and then the rotational energy is enough to bring me off the ground a little.
If the little knee bend is what could be causing this I will try to work on it when i'm better on 1/2 speed serves. Although my shoulder feels better now I think i'm going to wait a bit even if I get the all clear from the physio. Still waiting for the first appointment
Whilst i'm recovering i'm trying to find a better camera like the casio you've mentioned. I've tried looking already but they are hard to find now and expensive.