£205k plus admin fees Section 20 works?

I am a leaseholder in a block of flats in London. I have recently received a postal letter from our Managing Agent regarding Section 20 works being carried out on our building. This letter appears to be a Notice of Estimates, and references a previous letter, which I presume was a Notice of Intention that I never received.

This may be because I live abroad and the original letter never made it’s way to my forwarding address, though all correspondence with our Managing Agent is usually via email (which is my selected form of communication) so I’m unsure why they have elected to use a conventional letter as a means of communication in this instance.

Regardless, I am very concerned about the three estimates quoted, which are between 195k – 205k. This letter does not cite what the works are for, but does say that the Managing Agent has recommended going with a quote which is not the cheapest, and furthermore says that an 11% CDM administration fee and 5% S20 administration fee will be added on top of the total cost. this seems very excessive.

What rights do I have to fight this Section 20? Research suggests that the I can go to the First-tier Tribunal (Property Chamber), but I do not know on what grounds I can bring a charge. Does their failure to communicate the original letter via my selected form of correspondence (email) give me further grounds to reject this Section 20?

So far I have written to the Managing Agent (via email) asking for more details but they have not responded. I have called them and left messages but they have no rang back.

Many thanks for any welcomed advice!

Richard