The legal support back office folk, often organised by GBC, will have called the solicitor to let them know about the arrests and they may have received calls from the police on behalf of arrestees.
Depending on the action and number of arrests, the office folk might have asked the solicitor at each police station to liaise with you directly. You’ll be informed if this is the case.
Introduce yourself and your role and ask to be kept informed. Suggest that they pop out and chat to you once in a while so that fellow activists and legal support know what’s happening. It’s all too easy for them to swan into then station and be in there for hours with you outside none the wiser (and in some cases not even sure that they have arrived!)