Thorny, the answer to your question could be multi faceted. I hypothesise as follows;
Perhaps initially the ATSB wanted to conduct an investigation in line with its internal processes and ICAO annexe. However, possibly once the process commenced and after consultation with CASA they realised there may be a problem with one or two government departments looking like knobs as a result of some of the likely causal factors behind the accident.
Perhaps under the leadership of Beaker he quite stupidly decided to stop the retrieval so as to save a couple of pennies. It would not surprise me because he was relatively new to ATSB and had no idea about aviation accident investigations etc.
CASA the 'alpha male'. Perhaps the dominating partner in the marriage of CASA and ATSB is CASA? Normally there would be no marriage at all, but CASA saw a weakness in 'the new world according to Beaker' and CASA went where it had never been able to go before and have the ATSB become its bitch. Either way you have Doc Voodoo to mostly blame for this unholy agency conjugal relationship.
Good ol incompetence. Perhaps this whole sordid untidy affair can be pinpointed to plain old incompetence. You know, when egotistical nupties think they know everything when in fact they know ****. That's why companies are sold off by governments and the private sector takes over, governments are a totally useless waste of air.
Now all said and done, perhaps Nutella is the smoking gun? I've seen things that Nigella Lawson has done with Nutella which proves it is most certainly an underestimated foe, an unmitigated risk, a latent condition indeed
