matchseller
Whilst the Transitional payment can be affected by a Change of Circumstances, ESA has no Dependant Allowance and so your daughter turning 18 will not count as a C of C. I see nothing in the ESA Transitional Regulations that covered the transfer from IB to ESA that would now have effect, so I would expect your payments to continue as they are now.
That said, I would still be tempted to write to the DWP about the change just to cover yourself.
Gordon
Nothing on this board constitutes legal advice - always consult a professional about specific problems 
