Sarah_a82
From your post, it sounds like you are receiving what is now called legacy ESA this is a single benefit with payments based on your household income and assets and/or your Contribution history.
So yes, if you exceed the £16,000 limit you will lose entitlement to the ESA(IR) component but will remain entitled to the ESA(CB) part.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems