Council refusal on backdating H&CT Benefit ( re ILR )

[lindawall]

Recently I recieved my ILR (but children & spouse's status were all separately pending for respective complex reasons), so I sought specialist advice which took two weeks to find/obtain, to ensure my eligibility to claim Housing and Council Tax Benefit.
The Council had no idea on such complex matters and Home Office phone clerks certainly would not advise.
I claimed and was granted H&CT Benefit, but my application backdate to the date I recieved ILR was refused. The Council absurtedly stated that I should have contacted the Council to begin my claim provisionally before applying for ILR - but we all know that doing so could have caused complications fatal to an ILR application or interview (if where prior to ILR one has no recourse to public funds)!
Council says I did not show 'continuous good cause' for not applying in the the short period between grant of ILR and my obtaining advice / confirmation of eligibility shortly thereafter.
Is that a pigheaded Council decision?