Hello, I am Keith, one of the experts on Just Answer, and pleased to be able to help you with your question.
Savings, which is what the liberated pension amounts to, affect tax credits as follows [source: netmums.com]:
'Anything over £6000 will affect benefits, anything over £16k will stop them altogether.'
So if you have liberated more than the sums indicated this will be taken into account by the Tax Credit Office (TCO) in assessing your entitlement. If the TCO have got it wrong, a common occurrence, you should write to the them and demand an explanation. The TCO are very keen to make assumptions, in my experience invariably incorrect, and always in favour of the revenue. Their contact details you can find here:
I do hope that you have found my reply of assistance.