Mortgage overpayment

ces1234

Hi,
Just wondered if anyone could clarify things for me.


For simplicity my remaining mortgage debt is £100,000 and I've about 20 years left, and current interest rate is 4.45%


I want to overpay my mortgage, which I can do up to 10% of the remaining balance each year.


My mortgage company have said I have 2 options;
option 1 - keep my payments the same and reduce my mortgage term - this will cost me £30 and they will have to do 'checks' (they were a bit vague about this, I presume they wish to go through my payslips/bank statements)
option 2 - they reduce my monthly payments but keep the mortgage term the same.
They will not give me any advice as to how these 2 options compare in reality.
The online calculators I've used all seem to use option 1


Does anyone know how much difference in reality there would be with a one-off overpayment?
As things stand my mortgage year runs July-July so I suspect I will not have time to do option 1 before this July (and whilst I know financially things are ok hence I'm doing an overpayment my recent holiday has somewhat skewed my finances so I'm not sure I want them going though my statements with a fine toothcomb!)


Thanks!