Leasehold Flat - Property Management Woes

I live in a leasehold flat in London. c. 110 years left on the lease. It's 1 of 11 flats (Victorian conversion). I'm having terrible trouble with the property management company. The usual things:
* escalating service charges
* important works not being carried out (an electrical problem, 3 sections of broken guttering, frost damage to brickwork, long overdue exterior repainting, etc.)
* phone calls, emails, etc. being routinely ignored over a period of years.

What I would like to do is to fire the property management company and either appoint another company or, in fact, for the leaseholders to club together and manage things ourselves. A RTM company already exists for that purpose, and it has 11 shareholders (each leaseholder has 1 share).

I'm under the impression that a majority of leaseholders (ie 6 or more from the 11) would need to vote in order to make such a change. However I'm having trouble contacting some of them. Most of them don't live here (absentee landlords) and I don't expect the freeholder would be able/willing to give contact details. I have all their names (publicly available from the Companies House website) but for 7 or 8 of them I have no email address or phone number.

Can anyone advise how I should proceed? If I do nothing, the situation will just roll on. Do I have any right to insist that the property management company passes the other leaseholders' contact details to me (I would not have thought so)? Or, failing that, might I just approach the tenants of the various flats directly and ask if they can put me in touch with the owner/letting agent?

[The guy who runs the property management company is also the freeholder of the building - does that complicate matters?]

Thanks,
Alan