In a lease transfer who needs an ID1?

My wife and I are transferring a lease (one flat in a house with four flats) to my son. The freehold is owned by a limited company and the transfer of the lease includes one share in the company. There are four leaseholders each of whom owns one flat and one share in the company. My wife and I who are joint leaseholders and my son have each completed an ID1. My conveyancer tells me that the other three leaseholders also need to complete an ID1. This is very inconvenient as completion of an ID1 includes provision of bank statements or bank access, and one of the other leaseholders is abroad. Are these extra ID1s really needed? 

Anthony - all parties to a transfer must have their identities verified. Our practice guide explains in more detail - Practice guide 67: evidence of identity - GOV.UK

Yes. I've read that. But in this situation I would have thought that the only parties to the transaction are the disponsors and the applicant all of whom have been ID1-ed. The only other party is the freeholder company which (again according to your guidelines) may need to be searched. The other leaseholders are not parties because they have no power to stop or facilitate the transaction as its not their lease. No?  - or are you saying that all shareholders of a limited company involved in a land registration must be ID1? 

Anthony - the legal ownership is always transferred as a whole but it has nothing to do with the shares in the company
If I have understood your post correctly the freehold is owned by a limited company so there is no transfer of the freehold title. The only transfer is by the two of you to your son. If so then the only identity verification we need is for the three of you, not the company.
The conveyancer may be asking for other identities to be verified for their own needs but do check with them to confirm and to explain why they are needed 

Thank you. I realise this is a tricky subject.