Hi Diane - all parties to the Transfer need to have their identities verified.
If one party is legally represented then you would need to complete form AP1 as appropriate -
Completing the evidence of identity panels on forms AP1, FR1, DS2 - GOV.UK
If you are not using a conveyancer then you would need to have your identity verified using form ID1/conveyancer or form ID3/others as listed in PG 67