https://www.slab.org.uk/faqs/no-instructions-taken-by-the-nominated-solicitor-in-custody-cases/
Solicitors can sometimes delegate the entire initial stages of a case to another solicitor, including taking the initial instructions in the police station or the court cells area.
Question: Can appointed solicitor ABWOR still be provided in these circumstances, by the original solicitor?
Answer: No. Appointed solicitor ABWOR is firmly restricted to the solicitor who meets the conditions for/of instruction, and delegation options relate only to the subsequent appearance.
The taking of the instructions is not delegable. The solicitor taking the instructions and providing representation can do this in their name, as long as they also have a prior relationship.
Relevant legal aid guidance: Definition of “appointed solicitor” and principal criteria for acting