is it basically saying they had to have the banns read out in the churches of St Bride, St Bennett Pauls Wharfe and St Martins Ludgate?
No, these are the parishes in which the marriage was allowed to take place.
Marriage by licence was an
alternative to marriage after banns. Instead of waiting three weeks for banns to be called, one of the spouses, usually the groom, sometimes supported by a relative or close friend (bondsman), would swear an oath (allegation) that there was no legal reason why the marriage could not take place. He would sign a bond for a substantial sum, which would be forfeited if the statement was later found to be untrue.
There are lots of threads on these boards about why people might choose to marry by licence – you can use the
Search function at the top of the page.
The
FamilySearch wiki also has a good entry
https://familysearch.org/wiki/en/Marriage_Allegations,_Bonds_and_Licences_in_England_and_Wales