These are estimated to arrive at Sebart later this month and will hopefully be available for sale soon after. The UK price isn't yet confirmed but the Euro price has been listed as 500 Euros. This is pretty good when you consider that it includes the retracts and door sequencer. The turbine conversion kit (including mount, pipe and tank) is listed at 60 Euros.
if anyone in the UK would like to pre-order, either the turbine or EDF version, then please send me a PM.