Tango
We don't advise on Housing Benefit on the forum but my understanding is that HB does not operate in the same way as ESA in as much as the calculation is whether you receive HB or not and the banding that you fall within, so I suspect that even with the deduction of your pension your banding has not changed.
If you are still in doubt then I would suggest that you get face to face advice from a trained advisor, do an internet search for "welfare advice" with your postcode, town or county.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems