How to challenge unreasonable leasehold charges?

Hi there, bit of a steer if I may on my leasehold flat. Out of the blue our Freeholder appointed a new agent and we received the following whopping bill for the next 12 months:

General Building Repairs/Works £ 500.00
Accountancy Fees £ 168.00
Management Services £ 931.67
Bank Charges £ 30.00
Emergency out-of hours service £ 24.00
Health & Safety Assessments £ 60.00
Buildings Insurance £ 1,530.56
TOTAL £ 3,244.23

The property is two leaseholds in a Victorian terrace so this is split between two and for the last 14 years we’ve paid ground rent and building insurance each and every year with no issues.

The building insurance has increased by over 100%, and the dates are incorrect. They are demanding payment for a period that we have already partially covered last year, for both insurance and ground rent.

This feels super crooked to me with jumped up costs, there literally is zero to little costs managing this property. The communal area is just a front door and 2sqm entrance, the roof was replaced 14 years ago.

How can these been deemed as reasonable charges and what recourse do we have to fight? I guess not much I’ve contacted the other leaseholder who is equally in shock and we are looking to Right To Manage which will take time of course.

Any advice would be greatly appreciated.

Thanks,

Chris