I know ur serious chas but I just gotta agree with slave.
UR self launch antics post comes over very much like a follow on quote from the Monty P. theme running lately

Dont stress Chas - help is on the way

I'm going to call it the "Hydro-Launcher" aka "the X Bag".
NB:
- there is a patent pending for the commercially produced unit which is currently with my R&D team in the final stages of its 3 yr development strategy.
- this is strictly confidential information for chas only to test out the basic principles..
- no affiliation to the 'turbo'.U will need -:
- one large wine cask bladder.
- one length of dripper tube.
- one brick.
- and a piece of string.
Method -:
Using the string; attach the brick to one end of the dripper tube.
Fill the bladder to the brim with water.
Set everything up ready for launch procedure.
Dig a bladder size divot into sand just off the wing tip.
Place brick end of dripper tube in the hole.
Place the filled bladder on the wingtip.
nb make sure pourer points down & is just off the trailing edge.Open pourer tab & insert free end of dripper tube securely enough to ensure the bladder stays attached to the brick during the launch initiation.
When all set remove thumb from 'out' orifice end of the tube.
Commence countdown immediately.*
(see below)Race back - attach - tighten lines - cross-check & prepare for take-off.
*NB Countdown time span & hence numerical start point will depend on bladder size, kite size, wind strength, dripper orifice dimension & other such variables. I suggest having an accomplice on hand until u have the range fully sussed. My patented version will hit the market with a full & accurately charted gauge for u to refer to prior to set-up.
Coming to a kite store near you - soon.
YEAH - Im gunna be RICH