Thanks for your detailed responseI didn't think this was as long until I saw it posted.
Chapter and verse, not so. You're obliged by law to give your name. If you don't give your name you're peaking his interest in you and making him believe you are doing something wrong. He is wondering is their a warrant out for you or thinking if he runs you through PULSE will you show up as a known drug or weapon carrier and you will lose any good grace he was willing to show you.
Identify yourself and say you feel his questions are a little intrusive as you don't have a criminal record or have never been arrested (so long as that bit is true) and you feel that you should speak to a solicitor if the questioning continues. The guard knows he only has you on a whim. Be polite, wish the guard a good day and tell him you would like to leave. Always be polite and don't break eye contact. After identifying yourself you are allowed to stay silent. Worst case scenario he takes you to the station where you remain silent, a solicitor will come and you're out in no time charge free.
If you have a record you're actually in a better position than the man without one. You tell him you're name and then tell him I'm ringing my solicitor, you're picking on me cos of who I am, you're not stopping anybody else or at least I didn't see you. We'll see what my solicitor has to say about you stopping me on the street and I'm going to the Ombudsman about for you stopping me for nothing. He won't want the grief of it all incase it can be construed as picking on you.
See the guards uphold the law. But the laws are written up in your favor and not the guards. Don't be letting the thoughts of the wife or family into your head because that shows on your face and to the guard it just looks like guilt over what he has stopped you for.
Identify yourself politely and stay calm.