And does the civil marriage constitute nikah and class the couple as husband and wife in an Islamic context?
In the name of Allah, Most Compassionate, Most Merciful.
The conditions for a nikah to be valid according to Shariah are that there should be offer and acceptance (from the couple or a proxy) in one session, which should take place in the presence of two adult male witnesses or one adult male and two adult female witnesses. (Hidayah, Vol 2, P305-306)
If the above conditions are found in the civil marriage then the nikah will be valid in Shariah and the couple will be classed as husband and wife and therefore will not be in sin if they meet. However if any of the above conditions are not met in the civil marriage (i.e. offer and acceptance did not take place or the two required witnesses are not present) then the couple will not be classed, as husband and wife and therefore it will not be permissible for them to meet.
Only Allah knows best.
Darul Ifta, Birmingham