Thanks to everyone for the responses - an animated discussion for a Friday. :-)

There does seem to be a general division in responses from those I've received both privately and publicly.
Perhaps not surprisingly, the Regulators appearing to be looking for the detail and the consultant / developer side saying we (as regulators) shouldn't worry ourselves about the details and trust the works will be done to the required spec.

In response to Frank Westcott's comment, I agree that "Responsibility for securing a safe development rests with the developer and/or landowner".  In Scotland, PAN33 also says “…that the responsibility for the safe development of the site rests with the developer.”

However I don’t take this to say the LA should  to abdicate all responsibility to the developer.  If we did and works were not done correctly, the Court of Public Opinion would likely take a rather dim view of the lack of regulatory oversight from the Planning Authority in the development process.  Questions would (rightly) be asked) how did XXXX Local Authority let this happen? 

PAN 33 also states  “ Where development is proposed on contaminated land, the planning system is the appropriate mechanism for tackling remediation, either as a part of the planning application, or by conditions….. The planning authority should ensure that the land is made suitable for the proposed use.” - How does A LA fulfil this duty without scrutinising the remediation proposals?

Local Authorities are also seen (perhaps wrongly) as a means of last resort - even when the LA may have no legal responsibility to address land contamination issues on private land, LA's seem to often end up footing the bill to fix land contamination problems which are found to arise as a result of historical contamination and poor development practices.  Private companies go into liquidation with alarming frequency when liabilities rear their heads and I do have concerns with the modern practices of setting up shell companies for each and each new  development – the purpose of which would appear to be to protect and legally separate a parent company from liabilities associated with a particular project – if trouble arises - one can wind up the shell company and leave the parent company intact and scot-free.

I also take issue with the notion that by somehow requiring the developer to submit the detail of how they propose to implement their remedial works somehow infers "design liabilities to the Planning Authority through zealous checking of developers detailed designs or specifications.”
We are not designing it – simply asking for the designer to provide the detail by about the works they have designed.   

In the interests of being enabling in Planning trying to minimise the number of planning conditions placed on a consent , We (collectively) may be guilty of using loose terminology, thinking a Remediation Strategy is synonymous with a remedial methods statement , however if the developers are going to become cute about the interpretation of words and not providing sufficient information, perhaps we will need to be more precise and prescriptive about what we require -  and look for planning condition precisely aligned with CLR11 to avoid ambiguity -  - these would be around requirements for 

1) SI report & Risk assessment condition;
2) Detailed Remedial Options Appraisal Condition;
3) Remedial Strategy Condition ;
4) Implementation Plan Condition; and  
5) Verification Condition.

After all, Section 4.1 of CLR 11 (Implementation of the remedial Strategy) states 
“As a result, remediation may be implemented as a standalone contract or as an integral part of a development-related or other infrastructure project. An important first task is the development of an implementation plan, which deals with all aspects of the design, preparation, implementation, verification, and long-term monitoring and maintenance of remediation.”

This appears to require the developer to collate the necessary information which we are looking for.
Regards
Gerry